A method for treating loose layers by combining inspection and grouting

Abstract

This invention belongs to the field of coal mine water control, specifically relating to a method for combined grouting treatment of loose layers, including: S1, determining the borehole positions in the treatment area: drilling several boreholes at equal intervals in the treatment area, the boreholes being arranged in a quincunx pattern, with the borehole spacing... d The drilling depth is 25m~60m; S2, Drilling and Well Completion: Each borehole has a two-stage structure, with the first stage drilling to the top of the loose layer treatment section; S3, Hole Sweeping and Extension Drilling: Each borehole is divided into several treatment sections; according to the design and construction sequence, sweeping holes are arranged, and the holes are sweeped and then extended downwards for the length of one treatment section. l S4. Grouting-Inspection Coordinated Construction: Grouting is carried out in batches and sequences, with adjacent boreholes serving as inspection holes, achieving multiple uses for one hole; the treatment hole is also an inspection hole; S5. Similarly, repeat S3 and S4 until the entire treatment section is grouted; This invention optimizes the grouting treatment sequence to achieve coordinated treatment and inspection during the loose layer renovation project, promotes timely and dynamic improvement of the grouting scheme, and achieves optimal treatment effect.

Description

Technical Field

[0001] This invention belongs to the field of coal mine water control technology, specifically relating to a method for combined treatment and inspection of loose layers with grouting. Background Technology

[0002] Loose strata in coal seams are generally composed of clay, sand, and gravel, and are highly water-bearing. Improper handling can easily lead to water and sand inrush accidents, threatening safe underground mining. In previous surface grouting projects for loose strata, grouting control methods mainly included quantitative grouting and constant-pressure grouting. The grouting volume and stopping pressure were determined based on empirical values ​​or formulas. While this experience has certain applicability in the same region, in different regions with significant differences in geological conditions, empirical formulas (values) need to be adjusted according to the actual project, making it difficult to widely promote this grouting treatment method. Furthermore, existing grouting methods mainly focus on large-area multi-hole and group-hole grouting, with grouting effects primarily assessed post-construction. The effectiveness cannot be verified in a timely manner during construction, hindering the integration of treatment and inspection. In short, traditional grouting control methods have poor applicability under different geological conditions, and the grouting effect is difficult to verify in a timely manner.

[0003] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a grouting treatment method that combines treatment and inspection of loose layers. It adopts a multi-purpose approach to achieve parallel progress of grouting treatment and effect inspection. During the treatment process, treatment holes and inspection holes are no longer distinguished, and "injection" replaces "inspection", thus achieving synergy between treatment and inspection.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for treating loose layers using a combined grouting and inspection approach includes the following steps:

[0007] S1. Determination of borehole locations in the treatment area: Several boreholes are drilled at equal intervals in the treatment area, arranged in a quincunx pattern, with a borehole spacing d of 25m~60m; the boreholes are divided into the first row, second row, third row, fourth row... Nth row according to the grouting sequence;

[0008] S2. Drilling and Well Completion: Each borehole is a two-stage structure. The first stage is drilled to the top of the loose layer treatment section. The casing is then lowered into each borehole to the bottom of the first stage, cement grout is injected, and the casing is allowed to set for 24-48 hours until it is completely fixed.

[0009] S3. Hole cleaning and extension drilling: Each hole is divided into several treatment sections; according to the design and construction sequence, holes are cleaned and then extended downwards for one treatment section length l; the sum of all treatment section lengths l for each hole is denoted as the treatment section length L;

[0010] S4. Grouting-Inspection Coordinated Construction: Use cement or a mixture of cement and fly ash with a specific gravity of 1.3~1.8 for grouting. For the first stage of treatment, grouting is carried out in sections. First, odd-numbered rows of holes are used as grouting holes, and even-numbered rows of holes are used as inspection holes. Calculate the time T required for the grout to diffuse from the grouting holes to the inspection holes. If all inspection holes have grout flow within T time, the grouting of this batch is completed; otherwise, the holes that have not flowed are marked. Then, even-numbered rows of holes are used as grouting holes, and odd-numbered rows of holes are used as inspection holes. If all inspection holes have grout flow within T time, the grouting of this section of treatment is completed; otherwise, the holes that have not flowed are marked. Grouting is then carried out on the holes that have not flowed.

[0011] S5. Similarly, repeat S3 and S4 until the entire treatment section is grouted; count the number of times grout cross-flow occurs in all holes and calculate the cross-flow rate s.

[0012] Furthermore, in S1, the borehole spacing d is adjusted according to the water-bearing capacity of the loose layer. The borehole spacing d is 40m≤d<60m in the weak water-bearing zone, 30m≤d<40m in the medium water-bearing zone, 25m≤d<30m in the strong water-bearing zone, and 20m≤d<25m in the extremely strong water-bearing zone.

[0013] Furthermore, in S3, the first and second rows are first swept and drilled down by a treatment segment length l. After the subsequent grouting begins, starting from the third row, the holes are swept simultaneously for every two rows and then drilled down by a treatment segment length l.

[0014] Furthermore, in S2, the inner diameter φ of the sleeve is either 139.7 mm or 177.8 mm.

[0015] Furthermore, in S3, different treatment segment lengths l are selected according to lithology: the treatment segment length l in clay areas is 6m~10m, the treatment segment length l in sand areas is 4m~6m, and the treatment segment length l in gravel areas is 3m~4m.

[0016] Furthermore, the time T required for the grout to diffuse from the injection hole to the inspection hole is:

[0017] (1),

[0018] Where: d is the borehole spacing, in meters; l is the length of the treatment section, in meters; e is the porosity of the treatment section; Q is the grouting flow rate at the borehole opening, in cubic meters per second. 3 / h.

[0019] Furthermore, in S4, the cement grade is PO32.5 or PO42.5, and the fly ash is grade II or higher; in the cement and fly ash mixture, the mass ratio of cement to fly ash is 5:1 to 2:1.

[0020] Furthermore, in S4, when the lithology of the treated section is dense clay, the grouting flow rate Q at the borehole opening is taken as 3.12 m³. 3 / h; When treating sections where the lithology is mainly clay, the grouting flow rate Q at the borehole opening is taken as 5.4 m. 3 / h; When the lithology of the treatment section is mainly sandy, the grouting flow rate Q at the wellhead is taken as 9.6 m. 3 / h; When treating sections where the lithology is mainly gravel, the grouting flow rate Q at the orifice is taken as 15 m. 3 / h; When the lithology of the treatment section is entirely gravel, the grouting flow rate Q at the wellhead is taken as 23.4 m. 3 / h.

[0021] Furthermore, in S5, the formula for calculating the cross-contamination rate s is as follows:

[0022] (2),

[0023] Where, n c The number of boreholes where cross-contamination occurred is N, and the total number of all boreholes is N.

[0024] Furthermore, in S5, for boreholes without cross-grouting, the grouting pressure at the borehole opening must reach the grouting stop pressure P. t Stabilize for 1 hour, then stop injection port pressure P t Use 1.5 times the hydrostatic pressure before drilling and grouting.

[0025] The beneficial effects of this invention are:

[0026] This invention solves the problems of poor universality and delayed effect verification of traditional methods in the grouting process of loose layers. This invention optimizes the spatial arrangement of treatment boreholes and adopts a multi-purpose heating method for one hole. During the grouting process, there is no longer a distinction between treatment holes and inspection holes. Treatment holes are also inspection holes, thereby realizing the parallel advancement of grouting treatment and effect verification during the project process and achieving treatment and inspection synergy. Supplementary grouting is carried out based on the inspection results to improve the grouting treatment effect of loose layers. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0028] Figure 1 This is a schematic diagram of the drilling layout according to an embodiment of the present invention.

[0029] Figure 2This is a schematic diagram of the process of grouting the first treatment segment in an embodiment of the present invention. Figure 1 .

[0030] Figure 3 This is a schematic diagram of the process of grouting the first treatment segment in an embodiment of the present invention. Figure 2 .

[0031] Figure 4 This is a schematic diagram of the process of grouting in the second treatment segment according to an embodiment of the present invention.

[0032] Figure 5 This is a schematic diagram of the process of grouting the first treatment section of the first row of boreholes in an embodiment of the present invention.

[0033] Figure 6 This is a schematic diagram of the process of grouting the first treatment section of the third row of boreholes in an embodiment of the present invention.

[0034] Figure 7 This is a schematic diagram of the two-stage drilling structure according to an embodiment of the present invention.

[0035] Figure 8 This is a comparison image of rock cores before and after grouting in an embodiment of the present invention. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art are within the scope of protection of the present invention.

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0038] A method for treating loose layers using a combined grouting and inspection approach includes the following steps:

[0039] S1. Determination of borehole locations in the treatment area: Several boreholes are drilled at equal intervals in the treatment area, arranged in a quincunx pattern, with a borehole spacing d of 25m to 60m. The borehole spacing d is adjusted according to the water-bearing capacity of the loose layer. The boreholes are divided into the first row, the second row, the third row, the fourth row, ... the Nth row according to the grouting sequence.

[0040] S2. Drilling and Well Completion: Each borehole has a two-stage structure. The first stage is drilled to the top of the loose layer treatment section. Steel casing is then installed in each borehole to the bottom of the first stage. Grouting is then performed from the bottom using drill pipe until the grout returns to the surface through the annulus outside the casing. The grout is allowed to solidify for 24-48 hours until the casing is completely fixed. The above steps are repeated until all boreholes are drilled and wells are completed.

[0041] S3. Hole cleaning and extension drilling: Each borehole is divided into several treatment sections; according to the design and construction sequence, holes are cleaned and then extended downwards for one treatment section length l; the sum of all treatment section lengths l for each borehole is the total treatment section length L; for example... Figure 2 , Figure 3 As shown, the borehole is grouting the first treatment section. The area shown is the grouting treatment section of the loose layer. The total length L of the treatment section is the length from the bottom of the first section to the bedrock surface. Figure 7 The treatment section is schematically divided into 4 treatment segments (this is not the only case in actual working conditions), and the length of each treatment segment l and the total length of the treatment section L are marked.

[0042] S4. Grouting-Inspection Coordinated Construction: Use cement or a mixture of cement and fly ash with a specific gravity of 1.3~1.8 for grouting. For the first stage of treatment, grouting is carried out in sections. First, odd-numbered rows of holes are used as grouting holes, and even-numbered rows of holes are used as inspection holes. Calculate the time T required for the grout to diffuse from the grouting holes to the inspection holes. If all inspection holes have grout flow within T time, the grouting of this batch is completed; otherwise, the holes that have not flowed are marked. Then, even-numbered rows of holes are used as grouting holes, and odd-numbered rows of holes are used as inspection holes. If all inspection holes have grout flow within T time, the grouting of this section of treatment is completed; otherwise, the holes that have not flowed are marked. Grouting is then carried out on the holes that have not flowed.

[0043] S5. Similarly, repeat S3 and S4 until the entire treatment section is grouted; count the number of times grout cross-flow occurs in all holes and calculate the cross-flow rate s.

[0044] Furthermore, when arranging boreholes in S1, the treatment area is first divided into equilateral triangular meshes so that the distance between adjacent nodes is equal after the division, and the node positions are the borehole positions.

[0045] Furthermore, in S1, the borehole spacing d is selected according to the following table:

[0046] Table 1. Drilling Spacing Selection Table

[0047]

[0048] Furthermore, in S3, the first and second rows are first swept and drilled down by a treatment segment length l. After the subsequent grouting begins, starting from the third row, the holes are swept and drilled down by a treatment segment length l for every two rows simultaneously; only one row of holes is grouted each time.

[0049] Taking the first treatment section of the previous six rows of boreholes as an example, firstly, the first and second rows are swept and then drilled downwards for a treatment section length l; in this batch, odd-numbered holes are used as grouting holes and even-numbered holes are used as inspection holes. While grouting is being carried out on the first treatment section in the first row of boreholes and inspection holes are being used in the second row of boreholes, the third and fourth rows are swept and drilled downwards to the bottom of the first treatment section; as follows Figure 5As shown, the first and second rows of boreholes are about to be grouted and inspected, and the third and fourth rows of boreholes are being drilled in two stages to the bottom of the first treatment section.

[0050] Afterwards, grouting was performed on the third row of boreholes, inspection holes were drilled on the fourth row, and simultaneously, the fifth and sixth rows of boreholes were swept and drilled downwards to the bottom of the first treatment section, as shown below. Figure 6 As shown, the first and second rows of boreholes have been grouted, the third and fourth rows of boreholes are about to be grouted and inspected, and the fifth and sixth rows of boreholes have been drilled to the bottom of the first treatment section in the second stage; and so on until all boreholes have been drilled to the bottom of the first treatment section. Figure 2 The assumption is that there are a total of eight rows of boreholes (in actual construction, the number of boreholes is much greater), and all boreholes have been drilled to the bottom of the first treatment section. Figure 2 The diagram illustrates the working process where odd-numbered holes are used for grouting and even-numbered holes are used for inspection.

[0051] Then, even-numbered holes are used as grouting holes, and odd-numbered holes are used as inspection holes, until the first treatment section of all drilled holes is completed. Figure 3 A schematic diagram of the process of making grouting holes for even-numbered holes and inspection holes for odd-numbered holes; Figure 4 This diagram shows the completed first treatment segment for all boreholes. The black dots in the diagram represent the grouting areas.

[0052] Then the next round begins, namely the treatment of the second treatment section of the borehole. During the final borehole grouting of the first treatment section, the first and second rows of boreholes for the second treatment section are simultaneously swept and drilled downwards. Then the first and second rows of boreholes for the second treatment section are grouted and inspected, while the third and fourth rows of the second treatment section are swept and drilled downwards, and so on, until all treatment sections are grouted.

[0053] Furthermore, in S2, the inner diameter φ of the sleeve is either 139.7 mm or 177.8 mm.

[0054] Furthermore, in S3, different treatment segment lengths l are selected based on the lithology. The selection of treatment segment length l is shown in the table below:

[0055] Table 2 Selection Table for Treatment Section Length

[0056]

[0057] Furthermore, the time T required for the grout to diffuse from the injection hole to the inspection hole is:

[0058] (1),

[0059] Where: d is the borehole spacing, in meters; l is the length of the treatment section, in meters; e is the porosity of the treatment section; Q is the grouting flow rate at the borehole opening, in cubic meters per second. 3 / h.

[0060] Furthermore, in S4, the cement grade is PO32.5 or PO42.5, and the fly ash is grade II or higher; in the cement and fly ash mixture, the mass ratio of cement to fly ash is 5:1 to 2:1.

[0061] Furthermore, in S4, when the lithology of the treated section is dense clay, the grouting flow rate Q at the borehole opening is taken as 3.12 m³. 3 / h; When treating sections where the lithology is mainly clay, the grouting flow rate Q at the borehole opening is taken as 5.4 m. 3 / h; When the lithology of the treatment section is mainly sandy, the grouting flow rate Q at the wellhead is taken as 9.6 m. 3 / h; When treating sections where the lithology is mainly gravel, the grouting flow rate Q at the orifice is taken as 15 m. 3 / h; When the lithology of the treatment section is entirely gravel, the grouting flow rate Q at the wellhead is taken as 23.4 m. 3 / h.

[0062] Furthermore, the grout cross-contamination rate s in S5 reflects the grouting construction effect. The higher the grout cross-contamination rate s, the denser the cement grout veins formed by the grout in the loose layer, and the better the treatment effect. The formula for calculating the grout cross-contamination rate s is as follows:

[0063] (2),

[0064] Where, n c The number of boreholes where cross-contamination occurred is N, and the total number of all boreholes is N.

[0065] Furthermore, in S5, for boreholes without cross-grouting, the grouting pressure at the borehole opening must reach the grouting stop pressure P. t Stabilize for 1 hour, then stop injection port pressure P t Use 1.5 times the hydrostatic pressure before drilling and grouting.

[0066] The following is a specific example of a treatment area with a weakly aquifer and loose layer.

[0067] A method for treating loose layers using a combined grouting and inspection approach includes the following steps:

[0068] S1. Mesh subdivision and borehole location determination in the treatment area: The treatment area is divided into equilateral triangular meshes so that the distance between adjacent nodes is equal after subdivision. The node location is the borehole location. The loose layer in the treatment area is weakly water-rich. According to Table 1, the borehole spacing is 45m.

[0069] S2. Drilling and Well Completion: The borehole is a two-stage structure. The first stage is drilled to the top of the loose layer treatment section, with a depth of 245m. A φ177.8mm steel casing is lowered to the bottom of the first stage. PO42.5 pure cement slurry is injected from the bottom using the drill pipe until the cement returns to the surface through the annulus outside the casing. It is allowed to set for 24 hours until the casing is completely fixed. The above actions are repeated until all boreholes are drilled and wells are completed.

[0070] S3, Hole cleaning and downward drilling: such as Figures 1 to 6 As shown, the borehole sweeping construction is carried out from right to left. First, the two rows of boreholes on the right side are swept and then drilled down by a treatment section length l. The rock type of the treatment section is sand. According to Table 2, the treatment section length l is taken as 5m. After the subsequent grouting begins, starting from the third row, the boreholes are swept simultaneously for every two rows and then drilled down by a treatment section length.

[0071] S4. Grouting-Inspection Collaborative Construction: Use PO32.5 cement with a specific gravity of 1.5~1.8 for grouting; from right to left, use odd-numbered rows of drill holes as grouting holes and even-numbered rows of drill holes as inspection holes; calculate the time T required for the grout to diffuse from the grouting hole to the inspection hole according to formula (1). If all inspection holes are grouted within T time, the grouting of this batch is completed; otherwise, mark the drill holes that have not been grouted; complete the next batch of grouting in sequence from right to left, using even-numbered rows of holes as grouting holes and odd-numbered rows of holes as inspection holes. Repeat the above actions until all holes have completed the first stage of grouting, and supplement the grouting of drill holes that have not been grouted; "Complete the first stage of grouting" means that the first treatment section of all drill holes has been grouted;

[0072] S5. Repeat steps S3 and S4 until the entire loose layer treatment section is grouted. Count the number of times grout cross-contamination occurs in all holes, calculate the cross-contamination rate, and re-grout the holes that have not experienced cross-contamination.

[0073] In this embodiment, the total number of grouting operations was 392, with 342 instances of cross-grouting. According to formula (2), the cross-grouting rate was 86%. For boreholes without cross-grouting, the grouting pressure at the borehole opening must reach the grouting pressure P at the cessation point. t Stable for 1 hour is sufficient, P t Take 1.5 times the hydrostatic pressure before borehole grouting. For example, if the hydrostatic pressure before grouting in a certain borehole is 2.1 MPa, calculate the grouting stop pressure P. t The pressure was 3.15 MPa; the core sampling results of the treated area before and after grouting were as follows: Figure 8 a represents the period before grouting. Figure 8 b represents the cement grout forming cement veins in the loose layer after grouting, effectively consolidating the loose layer.

[0074] Specifically, in S4, the borehole spacing d = 45m, the treatment section length l = 5m, the treatment section porosity e = 0.22, and the grouting flow rate Q at the borehole opening is 15 m³ / s. 3 When / h, T=38.9h is obtained according to equation (1);

[0075] The first row on the far right is grouted, and the second row is used as inspection holes. If all inspection holes are cross-grouted within T=38.9h, the grouting effect of this batch is achieved, and grouting is stopped (that is, if the inspection holes are cross-grouted within T=38.9h, grouting can be stopped in advance); otherwise, grouting is stopped after 38.9h, and the inspection holes that have not been cross-grouted are marked; the first section of grouting in odd-numbered rows is completed from right to left.

[0076] Then, grout the second row from the far right, and mark the third row as inspection holes. If all inspection holes are grouted within T=38.9h, the grouting effect of this batch is achieved, and grouting is stopped; otherwise, grouting is stopped after 38.9h, and the inspection holes that are not grouted are marked; the first section of grouting is completed from right to left.

[0077] This invention optimizes the grouting treatment sequence, thereby achieving coordinated treatment and inspection during the loose layer renovation project, promoting timely and dynamic improvement of the grouting scheme, and achieving optimal treatment results.

[0078] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0079] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0080] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for treating loose layers by combining inspection and grouting, characterized in that, Includes the following steps: S1. Determination of borehole locations in the treatment area: Several boreholes are drilled at equal intervals in the treatment area, arranged in a quincunx pattern, with a borehole spacing d of 25m to 60m. The borehole spacing d is adjusted according to the water-bearing capacity of the loose layer. The boreholes are divided into the first row, the second row, the third row, the fourth row, ... the Nth row according to the grouting sequence. S2. Drilling and Well Completion: Each borehole is a two-stage structure. The first stage is drilled to the top of the loose layer treatment section. The casing is then lowered into each borehole to the bottom of the first stage, cement grout is injected, and the casing is allowed to set for 24-48 hours until it is completely fixed. S3. Hole cleaning and extension drilling: Each borehole is divided into several treatment sections; according to the design and construction sequence, holes are cleaned and then extended downwards for one treatment section length l; the treatment section length l is 3m~10m, and different treatment section length l is selected according to the lithology; S4. Grouting-Inspection Coordinated Construction: Use cement or a mixture of cement and fly ash with a specific gravity of 1.3~1.8 for grouting. For the first stage of treatment, grouting is carried out in sections. First, odd-numbered rows of holes are used as grouting holes, and even-numbered rows of holes are used as inspection holes. Calculate the time T required for the grout to diffuse from the grouting holes to the inspection holes. If all inspection holes have grout flow within T time, the grouting of this batch is completed; otherwise, the holes that have not flowed are marked. Then, even-numbered rows of holes are used as grouting holes, and odd-numbered rows of holes are used as inspection holes. If all inspection holes have grout flow within T time, the grouting of this section of treatment is completed; otherwise, the holes that have not flowed are marked. Grouting is then carried out on the holes that have not flowed. S5. Similarly, repeat S3 and S4 until the entire treatment section is grouted; count the number of times grout cross-flow occurs in all holes and calculate the cross-flow rate s.

2. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: In S1, the borehole spacing d in the weakly water-rich area is 40m≤d<60m, the borehole spacing d in the moderately water-rich area is 30m≤d<40m, the borehole spacing d in the strongly water-rich area is 25m≤d<30m, and the borehole spacing d in the extremely strongly water-rich area is 20m≤d<25m.

3. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: In S3, the first and second rows are first swept and drilled down by a treatment section length l. After the subsequent grouting begins, starting from the third row, the holes are swept simultaneously for every two rows and then drilled down by a treatment section length l.

4. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: In S2, the inner diameter φ of the sleeve is either 139.7 mm or 177.8 mm.

5. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: In S3, the treatment section length l for clay areas is 6m~10m, the treatment section length l for sand areas is 4m~6m, and the treatment section length l for gravel areas is 3m~4m.

6. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: The time T required for the grout to diffuse from the injection hole to the inspection hole is: （1）， Where: d is the borehole spacing, in meters; l is the length of the treatment section, in meters; e is the porosity of the treatment section; Q is the grouting flow rate at the borehole opening, in cubic meters per second. 3 / h.

7. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: In S4, the cement type is PO32.5 or PO42.5, and the fly ash is grade II or higher. In the cement and fly ash mixture, the mass ratio of cement to fly ash is 5:1 to 2:

1.

8. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: In S4, when the lithology of the treated section is dense clay, the grouting flow rate Q at the borehole opening is taken as 3.12 m³. 3 / h; When treating sections where the lithology is mainly clay, the grouting flow rate Q at the borehole opening is taken as 5.4 m. 3 / h; When the lithology of the treatment section is mainly sandy, the grouting flow rate Q at the wellhead is taken as 9.6 m. 3 / h; When treating sections where the lithology is mainly gravel, the grouting flow rate Q at the orifice is taken as 15 m. 3 / h; When the lithology of the treatment section is entirely gravel, the grouting flow rate Q at the wellhead is taken as 23.4m. 3 / h.

9. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: In S5, the formula for calculating the cross-contamination rate s is as follows: （2）， Where, n c The number of boreholes where cross-contamination occurred is N, and the total number of all boreholes is N.

10. The method for combined treatment and inspection of loose layers with grouting as described in claim 1, characterized in that: In S5, the grouting pressure at the borehole opening must reach the grouting stop pressure P for grouting in boreholes without cross-grouting. t Stabilize for 1 hour, then stop injection port pressure P t Use 1.5 times the hydrostatic pressure before drilling and grouting.

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