Comprehensive inspection method for deep horizontal grouting anti-seepage project of refuse landfill

Abstract

The invention discloses a comprehensive inspection method for a deep horizontal grouting anti-seepage project of a refuse landfill, and relates to the technical field of horizontal grouting anti-seepage project inspection. The comprehensive inspection method comprises the steps that an original stratum permeability coefficient is calculated on site through a water injection test before grouting; detecting water quality; an anti-seepage grouting project is carried out; the stratum permeability coefficient after grouting is calculated; performing rock core inspection operation; cement-bentonite slurry is adopted for hole sealing operation; a measuring line is arranged, and the grouting seepage-proofing construction effect is analyzed; and leveling the field and carrying out long-term water quality monitoring operation. According to the comprehensive inspection method, a dynamic cooperation mechanism of geophysical prospecting guiding, fixed-point verification and long-term monitoring is constructed through the comprehensive inspection method of physical parameter detection, structure imaging, microscopic verification and environment feedback, multi-dimensional evaluation of the quality of the impermeable layer is achieved, limitation of a single detection means is avoided, and the detection efficiency is improved. A particle size analysis method and an X-ray diffraction method are adopted to carry out quantitative analysis on the filling degree of the cement grout, and errors caused by manual judgment are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of horizontal grouting anti-seepage engineering inspection, and particularly relates to a comprehensive inspection method for deep horizontal grouting anti-seepage engineering of a waste landfill site. BACKGROUND

[0002] At present, quality inspection of waste landfill site anti-seepage engineering mainly relies on single means, such as drilling core or local water injection test operation, and there are some problems in actual application process: the traditional method can only detect local points and cannot evaluate the overall continuity and stability of the anti-seepage layer; the evaluation of the cement slurry solidification state lacks quantitative standards and leads to strong subjectivity of the test results; the existing technology mainly focuses on short-term anti-seepage effect and lacks long-term tracking monitoring mechanism for groundwater pollution; the conventional geophysical prospecting method is not combined with core data depth, leading to large interpretation error. SUMMARY

[0003] The present application aims to provide a comprehensive inspection method for deep horizontal grouting anti-seepage engineering of a waste landfill site to solve the problem of limitations of quality inspection of waste landfill site anti-seepage engineering in actual application process.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: A comprehensive inspection method for deep horizontal grouting anti-seepage engineering of a waste landfill site, specifically comprising the following steps: Step S1, before grouting, uniformly selecting points in the grouting anti-seepage area, using hot water drilling method, determining the drilling depth by observing the color and composition of the flushing slurry flowing out of the casing, carrying out water injection test after reaching the target layer, and calculating the permeability coefficient of the anti-seepage target layer before grouting; Step S2, arranging 1 deep and 1 shallow monitoring well on the upstream and downstream of the grouting anti-seepage area, sampling the shallow well to monitor the water quality of the waste landfill layer, sampling the deep well to monitor the water quality change of the confined aquifer, and obtaining each detection factor index of the underground water; Step S3, using a caterpillar type percussion drill to drill, after reaching the target layer, carrying out anti-seepage grouting engineering by lowering the grouting pipe, recording the grouting hole number and grouting parameters, and determining the best quality inspection time through on-site cement slurry solidification test; Step S4, carrying out water injection test after grouting, calculating the formation permeability coefficient after grouting, adopting the uniform and random combination arrangement principle, setting quality inspection holes according to 2% of the total amount of grouting holes, dynamically adjusting the point of the quality inspection hole based on the inversion result of the ground geophysical prospecting, and increasing the inspection density of the key area to 5%~10% and reducing the non-key area to 1%~2%. Step S5, core sampling is performed on the quality inspection hole, and core inspection operation is performed, particle size analysis method and X-ray diffraction method are introduced to analyze the cement slurry filling degree in the sand and gravel layer and the proportion range of cement in the cement-sand and gravel combination; Step S6, a cement-bentonite slurry is used for hole sealing operation; Step S7, before and after the construction of the anti-seepage project, a measuring line is arranged, the inversion figure of the ground geophysical prospecting method is compared with the drill core column chart, and the grouting anti-seepage construction effect is analyzed; Step S8, the site is leveled, the water quality change before and after grouting is compared, and long-term water quality monitoring operation is carried out.

[0005] Preferably, the water injection test before grouting uses a drill constant water head water injection test to determine the permeability coefficient, and the water injection test after grouting uses a drill water head reduction water injection test to determine the permeability coefficient, and for the scene of ultra-low permeability coefficient, a laser water level gauge is added to improve the water level measurement accuracy.

[0006] Preferably, the water injection test uses a BHD-180G multifunctional full-hydraulic anchoring drill, and the core sampling uses a DPP-100 type automobile drill.

[0007] Preferably, the judgment method for reaching the target layer before grouting in step S1 is that the color and composition of the flushing slurry flowing out of the casing are observed, if gravel appears in the flushing slurry and the slurry color is relatively clear, it is considered that the target layer is reached.

[0008] Preferably, the underground water detection factor indexes in step S2 include the pH value, total hardness, total dissolved solids, heavy metals, organic matter, nitrate and ammonia nitrogen of the underground water.

[0009] Preferably, the judgment method for determining the best quality inspection time in step S3 is that cement slurry setting tests are carried out on the 12 closest grouting holes, water injection tests are carried out on the center points of the grouting holes on the 10th, 12th, 14th, 16th and 18th days, and when the permeability coefficient value tends to be stable and the cement slurry and sand and gravel are well cemented, the best quality inspection time is obtained.

[0010] Preferably, the grouting holes in step S3 are arranged in a quincunx shape, the row distance and the row distance of the grouting holes are both 2.0m, and the depth of the grouting holes is 3-3.5m into the sand and gravel layer.

[0011] Preferably, the depth of the quality inspection hole in step S4 is 2-3m below the depth of the grouting hole, and the core length in step S5 is not less than 4m.

[0012] Preferably, the ground geophysical method in the step S7 is a three-dimensional high-density electrical method, and the three-dimensional high-density electrical method measuring lines are arranged before and after the construction of the anti-seepage project, the electrode spacing is 1 m, the measuring line spacing is 5 m, the continuity of the grouting layer is judged by the variation of the apparent resistivity contour before and after grouting, and the comprehensive comparison is carried out in combination with the drill core columnar diagram.

[0013] Preferably, the long-term water quality monitoring operation in the step S8 includes a routine sampling test and a pollution factor key monitoring operation, and the monitoring period of the long-term water quality monitoring operation is not less than two years, and the period is 6 months.

[0014] Compared with the prior art, the application has the following beneficial effects: 1. The comprehensive inspection method of the application realizes multi-dimensional evaluation of the quality of the anti-seepage layer by combining the permeability coefficient test, core analysis, geophysical inversion and water quality monitoring, and avoids the limitation of a single detection method. 2. The method uses the ground geophysical inversion result to dynamically adjust the point of the quality inspection hole, reduces blind sampling, improves the pertinence of inspection, and realizes higher quality evaluation accuracy with fewer points. 3. The method uses the particle size analysis method and the X-ray diffraction method to analyze the cement slurry filling degree, upgrades the core inspection from 'qualitative observation' to 'quantitative analysis + microscopic verification', ensures the objectivity and accuracy of the inspection result, reduces the error of human judgment, and ensures the durability and stability of the anti-seepage effect. 4. The method combines the ground geophysical method with the drill core data in depth, feeds back the point inspection result (such as the permeability coefficient and the slurry filling rate) to the geophysical model, corrects the inversion parameters, improves the geophysical interpretation accuracy, effectively identifies the weak area of the anti-seepage layer, and provides a scientific basis for subsequent reinforcement construction. 5. The method sets a long-term water quality monitoring mechanism, regularly tracks the change of the underground water pollution factor, effectively blocks the migration of pollutants, and realizes long-term protection of the underground water environment. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a step schematic diagram of the comprehensive inspection method of the application.

[0016] Figure 2 It is a schematic diagram of the anti-seepage reconstruction project of the application.

[0017] Figure 3 It is a grouting before and after apparent resistivity comparison diagram of the application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the application more clear, the application is further described in detail below in combination with the drawings and examples.

[0019] The present embodiment takes a non-formal landfill site in Henan Province as an example, as shown in Figure 2 , the landfill site is mainly construction waste, with a small amount of industrial solid waste, including chemical waste, calcium carbide slag, fly ash, etc., without anti-seepage measures, there is a risk of landfill leachate polluting water bodies, the first aquifer roof in the landfill site is distributed with continuous silt and silty clay, which has a certain anti-pollution property, the pre-investigation found that there is an area of missing aquifer roof at the bottom of the landfill, which becomes the main channel for landfill pollution components to migrate into the aquifer, making the landfill directly contact with the first aquifer, and after a long time of leaching, etc., it will continuously release toxic and harmful substances such as hexavalent chromium, cadmium, lead, dichloromethane, etc., which directly enter the aquifer, thereby reducing the quality of groundwater and affecting the safety of drinking water for surrounding residents; The static pressure grouting technology of permeation grouting is selected to carry out grouting anti-seepage engineering, which is suitable for sandy soil above medium sand and fissured rock, which is consistent with the characteristics of the site grouting section mainly composed of pebbles and sand layer, the grouting material is cement-bentonite slurry, which is low in price and has good fluidity, good cementation, high stone strength and other characteristics, easy to control initial and final setting time, and meets the requirements of slurry diffusion; Due to the concealment of underground horizontal grouting engineering construction process, the underground horizontal anti-seepage layer formed is invisible, and it is difficult to test the continuity and stability of the anti-seepage layer and the anti-seepage effect, aiming at this technical problem, a comprehensive test method for landfill deep horizontal grouting anti-seepage engineering is proposed, as shown in Figure 1 , Figure 3 ; The anti-seepage grouting area in the present embodiment is 2400m 2 , and the anti-seepage engineering is arranged with multiple rows of vertical grouting holes 608, the grouting holes are arranged in a plum blossom shape, the grouting holes are arranged with a row distance of 2.0m and a row distance of 2.0m, the depth is 26-28m, the hole diameter is 134mm, the internal area grouting hole depth enters the sand and pebble layer 3.5m, the peripheral boundary area grouting hole depth enters the pebble layer below the silt 3m, the internal grouting hole grouting section length is 2.5m, and the peripheral boundary area grouting hole grouting section length is 3.0m, to ensure that the grouting forms a continuous and effective anti-seepage layer in the pebble layer.

[0020] Specifically, the following steps are included: Step S1, before grouting, uniformly select points in the grouting anti-seepage area, use hot water drilling method, determine the drilling depth by observing the color and composition of the flushing slurry flowing out of the casing, carry out water injection test after reaching the target layer, and calculate the permeability coefficient of the anti-seepage target layer before grouting; Specifically, 2400m 2The seepage coefficient of the seepage prevention target layer before grouting is measured at 6 points in the grouting seepage prevention area. In order to improve the drilling efficiency of the water injection test hole, the open water drilling method is used with the BHD-180G multifunctional full-hydraulic anchoring drill, using clear water as the flushing medium, the drilling speed is controlled at 1.0-1.5 m / min to avoid disturbing the stratum, the casing has an outer diameter of 168 cm and an inner diameter of 135 cm. Due to the uneven depth of the landfill, it is difficult to determine the depth of the aquifer, so the drilling depth is determined by observing the color and composition of the flushing slurry flowing out of the casing. If gravel appears in the flushing slurry and the slurry color is relatively clear, it is considered to reach the target layer, stop drilling, and lower the casing into the sand and gravel layer by 0.2-0.5 m to prevent water seepage from affecting the calculation results during the water injection test. The drill rod is removed and the casing is left in the borehole for water injection test. The target layer for water injection test is mainly sand and gravel with a large permeability coefficient. The constant water head injection test is used to determine the permeability coefficient of the grouting target layer, and the permeability coefficient of the grouting target layer is measured to be 1.98x10 -2 ~1.26x10 -3 cm / s. The open water drilling method is a drilling process using clear water as a flushing medium to reduce stratum disturbance.

[0021] Step S2, 1 deep and 1 shallow are arranged upstream and downstream of the grouting seepage prevention area, the shallow well is used for sampling and monitoring the water quality of the landfill layer, and the deep well is used for sampling and monitoring the water quality change of the confined aquifer to obtain the index of each detection factor of groundwater. Specifically, in order to comprehensively analyze the influence of landfill on groundwater quality, water samples are taken for detection to obtain the index of each detection factor of groundwater. The sampling test results show that the detection factor indexes affecting the quality of groundwater are mainly pH value, total hardness, total dissolved solids, and organic indicators of carbon tetrachloride, chloroform, and chloral.

[0022] Step S3, use the track-mounted percussion drill to drill, after reaching the target layer, carry out the seepage prevention grouting project, record the grouting hole number and grouting parameters, and determine the best quality inspection time through the field cement slurry setting test. Specifically, when the sandstone appears in the flushing slurry, it is considered that the target horizon is reached, the hole number and depth are recorded, the total grouting of the anti-seepage grouting construction is recorded, the grouting hole depth is 26-28 m, the cement slurry setting standard value is consulted, the cement slurry ratio, injection depth, temperature and other factors are comprehensively considered, and the on-site cement slurry setting test is carried out to determine the best quality inspection time. The judgment method for determining the best quality inspection time is: when the outdoor temperature is about -5 to +10℃ and the aquifer temperature is about 15 to 20℃ during construction, select the 12 closest grouting holes to carry out cement slurry setting test, and carry out water injection test on the 10th, 12th, 14th, 16th and 18th day respectively. When the permeability coefficient value tends to be stable and the cement slurry and sandstone are well cemented, the best quality inspection time is obtained. When the permeability coefficient is ≤6×10 -5 cm / s, there is no obvious gap between the slurry and the pebble, the interface is clear and firm, there is no delamination and loosening phenomenon, and it is determined that the cementation state is good. It is found in the embodiment that the cementation state of the cement slurry and the sandstone is good 14 days after the anti-seepage grouting is completed, and the permeability coefficient value tends to be stable, so the comprehensive inspection work is carried out 14 days after the anti-seepage grouting is completed.

[0023] Step S4, water injection test is carried out after grouting, the formation permeability coefficient after grouting is calculated, the layout principle of uniform and key area encryption is adopted, and the quality inspection hole is set according to 2% of the total amount of grouting holes; Specifically, referring to the number of inspection holes for consolidation grouting in “Technical Code for Grouting of Overburden Layer in Water and Hydropower Engineering” (DL / T 5267-2012) and “Technical Code for Cement Grouting of Hydraulic Structures” (SL / T 62-2020), the number of quality inspection holes in the embodiment is set to 2% of the total number of grouting holes. 2% of 608 holes should be 12.16, and 12 holes are arranged according to the rounding rule. The quality inspection holes are arranged at the center position of 3 grouting holes in the engineering area, 11 holes are distributed in the internal area of the anti-seepage engineering area, and 1 hole is distributed in the boundary area. According to the grouting depth of each grouting hole, the purpose layer depth of water injection test is determined; The permeability coefficient after grouting is greatly reduced, the permeability coefficient is measured by drilling dewatering head water injection test, the water injection test is unified to fill the drill casing with water as the initial water head, 10 measurements are carried out according to the specification, and the formation permeability coefficient after grouting is calculated on site. -6 ~3.81×10 -5 cm / s, which is significantly reduced compared with before grouting, reaching the permeability coefficient level of silty clay (1.2×10 -6 ~6.0×10 -5 cm / s); The quality inspection hole is constructed by using a BHD-180G multifunctional full-hydraulic anchoring drilling machine, water drilling method is adopted to drill to a position 4 m above the top plate of the grouting target layer, then a DPP-100 automobile drilling machine is used to start the lower coring operation, the BHD-180G multifunctional full-hydraulic anchoring drilling machine is replaced to lower the casing pipe in the grouting section, water injection test is carried out, and finally the DPP-100 automobile drilling machine is used again to core to the bottom boundary of the grouting diffusion to end the operation.

[0024] In step S5, coring is performed on the quality inspection hole, core inspection operation is performed, particle size analysis method and X-ray diffraction method are introduced, and the filling degree of cement slurry in the sand gravel layer and the proportion range of cement in the cement-sand gravel combination are analyzed; Specifically, the core inspection work is carried out by twice coring according to step S4, and the core length is not less than 4 m, and the sand gravel is taken as the criterion. Since the cement slurry is gray after solidification and has a color close to that of sand gravel, in order to avoid the error of naked eye observation, indoor material analysis methods such as particle size analysis method and X-ray diffraction method are introduced to analyze the filling degree of cement slurry in the sand gravel layer; Specifically, the particle size analysis method is based on the difference in particle size distribution of cement, sand and other components. By measuring the particle size distribution of the mixed material and combining the particle size characteristics of each component, the proportion of cement is calculated. A laser particle size analyzer and other equipment are used to analyze the particle size of the mixed material sample to obtain the particle distribution in different particle size ranges. According to the known particle size distribution characteristics of cement, sand and other components, a mathematical model is established to process the particle size analysis data. Through model calculation or algorithm analysis, the proportion of cement in the mixed material is determined. This method is suitable for occasions where the particle size distribution of the mixed material is clearly required or the particle size characteristics of cement, sand and other components are known, and can quickly and non-destructively preliminarily judge the proportion of cement. Specifically, the X-ray diffraction method is based on the different crystal structures of cement, sand and other components. Through X-ray diffraction analysis, the crystal structure characteristics of each component in the mixed material can be identified, and the content of cement can be determined. The mixed material sample is ground into powder to prepare a sample suitable for X-ray diffraction analysis. The sample is placed in an X-ray diffractometer for diffraction analysis, and the diffraction pattern is recorded. According to the characteristic diffraction peaks in the diffraction pattern, the crystal structure of cement, sand and other components is identified, and the content of cement is calculated by quantitative analysis method. This method is suitable for occasions where the crystal structure of the mixed material needs to be accurately analyzed, especially when different mineral components need to be distinguished. X-ray diffraction method can provide accurate component information. According to the sample test analysis, the proportion of cement in the cement-sand gravel combination in the anti-seepage engineering is 10% to 15% by volume ratio, which ensures that the cementing body has good strength and durability in the early and later stages.

[0025] Step S6, sealing hole operation is performed by using cement-bentonite slurry; Specifically, after coring, the automobile drill rod of the DPP-100 type automobile drill is pulled out, the grouting pipe is lowered into the casing, the outer diameter of the casing is 168 cm, the inner diameter is 135 cm, after the slurry is filled, the grouting pipe and the casing are pulled out, and the water-cement ratio of the sealing slurry can be adjusted according to the actual environmental requirements.

[0026] Step S7, before and after the construction of the anti-seepage project, the measuring lines are arranged respectively, the inversion figure of the ground geophysical prospecting method is compared with the drill core columnar diagram, and the grouting anti-seepage construction effect is analyzed; Specifically, the three common ground geophysical prospecting methods are three-dimensional high-density electrical method, seismic frequency resonance exploration method and high-precision magnetic measurement method, combined with the basic principles of each method, three measuring lines are arranged by using the three methods, and the inversion results are compared, and the three-dimensional high-density electrical method is selected as the quality inspection geophysical prospecting method; The measurement of three-dimensional high-density electrical method is based on the electrical difference of rock-soil body, a current is emitted in the medium, due to the different conductivity of underground medium, the distribution of the primary current changes, which causes the change of space potential, and then the potential observed on the ground is converted into resistivity, the seismic frequency resonance exploration is a kind of exploration method which uses the frequency resonance principle widely existing in nature to carry out seismic exploration and obtain the geometric and attribute characteristic parameters of underground geological body, the high-precision magnetic measurement method is based on the certain magnetic difference between steel slag and concrete block and the surrounding soil layer, which reacts to the steel slag, concrete block and other engineering waste landfill, these landfill can cause magnetic anomaly and reflect the position of steel slag and concrete block; The three-dimensional high-density electrical method is selected as the ground geophysical prospecting method, 9 three-dimensional high-density electrical measuring lines are arranged before and after the construction of the anti-seepage project, the electrode spacing is 1 m, the measuring line spacing is 5 m, the continuity of the grouting layer is judged by the change of apparent resistivity contour before and after grouting, and the drill core columnar diagram is comprehensively compared, the grouting layer position can be judged, the influence of noise points can be effectively removed, the apparent resistivity is the apparent resistivity measured by the three-dimensional high-density electrical method, which is used to reflect the electrical difference of the stratum; Specifically, the specific steps of analyzing the grouting anti-seepage construction effect are: selecting the Vth geophysical line, such as Figure 2 and Figure 3As shown, the apparent resistivity contour lines of the section to be grouted and the nearby section are sparse, disordered, curved and discontinuous before grouting, and the apparent resistivity contour lines of the grouted section and the nearby section become dense, flat, continuous and layered after grouting, indicating that the voids of the grouted section and the nearby section are completely filled, and the stratum is complete and continuous, so the electrical properties are uniform and stable. The grouting holes are located on one side of the 51-135 m section of the V-line high-density electrical profile, the grouting depth is 23-29 m, the grouting thickness is 2.5-3 m, the apparent resistivity value of the grouting section and the nearby section before grouting is 25-38 Ω·m, and the average value is 32 Ω·m. The apparent resistivity value of the grouting section and the nearby section after grouting is 38-87 Ω·m, and the average value is 54 Ω·m. The apparent resistivity value after grouting is larger than that before grouting, and it is speculated that the stratum of this section is greatly affected by grouting, and the cement slurry filling is obvious and continuous. According to the core records of the nearby detection holes, the JY1 detection hole is located 2.5 m north of the No. 62 electrode of the V-line high-density electrical profile, and the cement slurry filling of the 26.5-27.5 m section of the core is obvious. The JY3 detection hole is located 2.5 m north of the No. 77 electrode of the V-line high-density electrical profile, and the cement slurry filling of the 25-29.2 m section of the core is obvious. The JY11 detection hole is located 0.5 m north of the No. 120 electrode of the V-line high-density electrical profile, and the cement slurry filling of the 27-31.4 m section of the core is obvious. The results are consistent with the geophysical interpretation results, and the results of geophysical interpretation and core comparison prove that the repaired water-resisting roof is continuous and stable.

[0027] Step S8, leveling the site, comparing the water quality changes before and after grouting, and carrying out long-term water quality monitoring operation; Specifically, the main pollution source of the landfill is calcium carbide slag, and the main component is Ca(OH)2. The calcium carbide slag and leachate are strongly alkaline, and the pH value of the slag liquid is above 12. pH value automatic monitoring equipment needs to be equipped in the downstream deep monitoring well to obtain the pH value of groundwater in real time, and the hexavalent chromium, cadmium and manganese in the groundwater need to be controlled. Specifically, the long-term water quality monitoring operation includes routine sampling and testing and pollution factor monitoring operation. The monitoring cycle of the long-term water quality monitoring operation is not less than two years, and the cycle is six months. The test indexes include potassium, sodium, calcium, magnesium, cadmium, lead, arsenic, chloride, sulfate, nitrate, total nitrogen, hexavalent chromium, carbonate, bicarbonate, total hardness, total dissolved solids, organic matter, etc. By comparing the water quality test results before and after grouting, if the index content in the groundwater sample does not exceed the limit value of groundwater class III water, the indexes such as chloride, sulfate and total nitrogen obviously and continuously decrease, indicating that the water quality is obviously improved.

[0028] In summary, the comprehensive inspection method is used to inspect the continuity and stability of the underground horizontal grouting anti-seepage engineering from multiple aspects such as the permeability coefficient, cement-sand gravel cementing degree, formation inversion, and groundwater quality. The water injection test and core inspection can accurately inspect whether the random point reaches the anti-seepage effect, whether it can effectively block the downward migration of the pollution factors in the landfill into the aquifer channel, and the formation is inverted through the geophysical prospecting means. Combined with the water injection test results and core sample indoor test, the continuity of the grouting anti-seepage layer can be effectively analyzed, the point needing to be re-grouted due to the non-standard anti-seepage effect can be obtained, and the monitoring frequency can be improved.

[0029] The above merely describes the specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which shall be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A comprehensive inspection method for landfill deep horizontal grouting anti-seepage engineering, characterized in that, Specifically comprising the following steps: Step S1, before grouting, uniformly selecting point positions in the grouting anti-seepage area, using the open water drilling method, determining the drilling depth by observing the color and composition of the flushing slurry flowing out of the casing, conducting water injection test after reaching the target horizon, and calculating the permeability coefficient of the anti-seepage target layer before grouting; Step S2, arranging 1 deep and 1 shallow monitoring well on the upstream and downstream of the grouting anti-seepage area, sampling and monitoring the water quality of the landfill layer in the shallow well, sampling and monitoring the water quality change of the confined aquifer in the deep well, and obtaining the underground water detection factor index; Step S3, using a track-type impact drill to drill, after reaching the target horizon, carrying out anti-seepage grouting engineering by lowering the grouting pipe, recording the grouting hole number and grouting parameters, and determining the best quality inspection time through on-site cement slurry setting test; Step S4, after grouting, conducting water injection test to calculate the formation permeability coefficient after grouting, adopting the uniform and random combination arrangement principle, setting quality inspection holes according to 2% of the total number of grouting holes, based on the inversion results of ground geophysical prospecting, dynamically adjusting the point positions of quality inspection holes, increasing the inspection density of key areas to 5%~10%, and reducing the inspection density of non-key areas to 1%~2%; Step S5, coring the quality inspection holes, conducting core inspection operation, introducing particle size analysis method and X-ray diffraction method, and analyzing the cement slurry filling degree in the sand and gravel layer and the cement proportion range in the cement-sand and gravel combination; Step S6, using cement-bentonite slurry to seal the hole; Step S7, arranging measuring lines before and after the construction of the anti-seepage engineering, comparing the inversion graph of the ground geophysical prospecting method with the drilling core column chart, and analyzing the grouting anti-seepage construction effect; Step S8, leveling the site, comparing the water quality change before and after grouting, and carrying out long-term water quality monitoring operation.

2. The integrated inspection method of claim 1, wherein, The water injection test before grouting adopts the constant water head drilling water injection test to determine the permeability coefficient, the water injection test after grouting adopts the drilling water head reduction water injection test to determine the permeability coefficient, and for the scene of ultra-low permeability coefficient, a laser water level gauge is added to improve the water level measurement accuracy.

3. The integrated inspection method of claim 1, wherein, The water injection test adopts a BHD-180G multifunctional full-hydraulic anchoring drill, and the coring adopts a DPP-100 type automobile drill.

4. The integrated inspection method of claim 1, wherein, The judgment method for reaching the target horizon before grouting in step S1 is that the color and composition of the flushing slurry flowing out of the casing are observed, if gravel appears in the flushing slurry and the slurry color is relatively clear, it is considered that the target horizon is reached.

5. The integrated inspection method of claim 1, wherein, The underground water detection factor index in step S2 includes the pH value, total hardness, dissolved total solids, heavy metals, organic matter, nitrate and ammonia nitrogen of underground water.

6. The integrated inspection method of claim 1, wherein, The judgment method for determining the best quality inspection time in step S3 is that the cement slurry setting test is carried out on the 12 closest grouting holes, the water injection test is carried out on the center point of the grouting hole on the 10th, 12th, 14th, 16th and 18th day, and when the permeability coefficient value tends to be stable and the cement slurry and sand and gravel are well cemented, the best quality inspection time is obtained.

7. The integrated inspection method of claim 1, wherein, The grouting holes in step S3 are arranged in a quincunx shape, the row distance and row distance of the grouting holes are both 2.0 m, and the depth of the grouting holes is 3~3.5 m into the sand and gravel layer.

8. The integrated inspection method of claim 1, wherein, The depth of the quality inspection hole in the step S4 is 2-3 m below the depth of the grouting hole, and the length of the core in the step S5 is not less than 4 m.

9. The integrated inspection method of claim 1, wherein, The ground geophysical prospecting method in the step S7 is a three-dimensional high-density electrical method, three-dimensional high-density electrical method lines are arranged before and after the construction of the anti-seepage project, the electrode spacing is 1 m, the line spacing is 5 m, the continuity of the grouting layer is judged by the change of the apparent resistivity contour line before and after grouting, and the judgment is compared with the drill core columnar chart.

10. The integrated inspection method of claim 1, wherein, The long-term water quality monitoring operation in the step S8 includes routine sampling and testing and pollution factor key monitoring operation, and the monitoring period of the long-term water quality monitoring operation is not less than two years, with a period of 6 months.

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