A method and system for evaluating the effect of stratum grouting reinforcement based on pressure ratio graph

Abstract

The application discloses a stratum reinforcement grouting effect evaluation method based on a volume-pressure ratio graph, which comprises the following steps: obtaining grouting data of each grouting section, and drawing a volume-pressure ratio graph of each grouting section according to the grouting data; the volume-pressure ratio graph comprises a grouting volume ratio line, a pressure ratio line and a ratio grid line; and whether the grouting effect of each grouting section meets the standard is evaluated according to whether the grouting volume ratio line reaches the left and right boundary lines of the ratio grid line and whether the pressure ratio line reaches the upper boundary line of the ratio grid line; the grouting pressure and the grouting volume are organically combined through the volume-pressure ratio graph, and a new method for evaluating the drilling grouting effect is displayed through the graph; the graph is simple and intuitive, and is convenient for identification; and whether the grouting reinforcement effect of a section of a drilling hole meets the standard can be rapidly evaluated through the graph.

Description

Technical Field

[0001] The present invention relates to the technical field of stratum grouting reinforcement effect evaluation, and specifically relates to a method and system for analyzing and evaluating the stratum grouting reinforcement effect based on a flow-pressure ratio diagram. Background Art

[0002] In the construction of foundation pits, tunnels and other underground works, when encountering loose, soft and water-rich surrounding rocks, natural disasters such as collapse, large deformation or water and mud inrush often occur, which bring serious troubles to engineering construction. Grouting reinforcement is one of the most effective methods to treat the above disasters. Generally, when performing grouting reinforcement in shallow loose, soft and water-rich surrounding rocks, a forward or backward segmented grouting process can be adopted. Segmented grouting refers to dividing the entire grouting section into several small sections in the grouting borehole for sequential grouting according to different stratum properties or hydrogeological conditions. The forward type refers to sequential segmented grouting from shallow to deep, and the backward type refers to sequential grouting from deep to shallow in a retreating manner after the grouting borehole is drilled. At the beginning of each grouting project, the hydrogeological conditions are not sufficiently understood. To ensure grouting safety and grouting reinforcement effect, before grouting the entire project, boreholes shall be constructed to explore the hydrogeological conditions of the surrounding rock in the grouting area, so as to determine the grouting depth and grouting section distance; through grouting tests in the exploration boreholes, combined with the type and capacity of grouting equipment and grouting materials, the safe grouting parameters (mainly grouting pressure and grouting amount) within each section distance are determined as reference values for subsequent grouting. These reference values can be used not only as the design values of the subsequent grouting reinforcement scheme, but also as the evaluation criteria, i.e., the compliance values, for verifying whether the subsequent grouting reinforcement effect is qualified. Only when the grouting parameters meet the standards can the grouting reinforcement effect be qualified.

[0003] At present, common methods for inspecting and judging the grouting reinforcement effect mainly include borehole methods, including borehole coring, borehole wall stability observation, borehole water pressure or pumping tests; grouting process data analysis methods such as the P-Q-T curve method and the grouting amount spatial distribution method; geophysical exploration inspection and comparison methods, etc. The borehole method inspects the stability of the stratum after grouting, the improvement of surrounding rock strength, and the reduction of porosity, that is, the improvement degree of water insulation capacity; the P-Q-T curve records the variation trend of pressure and grouting rate with time during a single grouting process, and the improvement of surrounding rock during grouting and whether the grouting process is normal can be analyzed by observing the data variation trend of pressure and grouting rate in the grouting process, so as to guide whether to continue or stop the current grouting. The grouting amount spatial distribution method counts the total volume of slurry injected in a certain grouting area, and inversely deduces and analyzes the porosity and grout acceptance capacity of the surrounding rock in the area through the difference in the total amount of slurry injected in different areas. The geophysical exploration inspection and comparison method uses geophysical means to explore the improvement degree of the stratum before and after grouting, that is, the reduction degree of water abundance.

[0004] The above-mentioned grouting effect evaluation methods all study individual indicators such as formation stability, porosity, pressure value, grouting rate, and water-bearing capacity. They reveal the relationship between these individual indicators and the grouting formation. However, the current grouting effect evaluation methods cannot accurately determine the grouting failure or weak grouting area, and there are difficulties in finding the grouting failure area. They cannot provide direct guidance for supplementary grouting reinforcement of the grouting failure area. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method and system for evaluating the effect of grouting reinforcement based on a pressure-volume ratio diagram. By drawing a pressure-volume ratio diagram, the grouting pressure and grouting volume are organically combined and displayed graphically. The diagram is simple, intuitive, and easy to identify, and the grouting reinforcement effect of a certain section of a borehole can be quickly determined through the diagram.

[0006] The technical solution of the present invention is as follows: In a first aspect of the present invention, a method for evaluating the effect of grouting for formation reinforcement based on a pressure-volume ratio diagram is provided, characterized by comprising the following steps: Acquire grouting data for each grouting section, and plot the volume-pressure ratio diagram for each grouting section based on the grouting data; the volume-pressure ratio diagram includes grouting volume ratio lines, pressure ratio lines, and ratio grid lines; The grouting effect of each grouting section is evaluated based on whether the grouting volume ratio line reaches the left and right boundary lines of the ratio grid line and whether the pressure ratio line reaches the upper boundary line of the ratio grid line.

[0007] In some embodiments of the present invention, the grouting data includes grouting volume, grouting pressure, drilling trajectory, grout diffusion diameter, and grouting depth.

[0008] In some embodiments of the present invention, the pressure ratio graph further includes a borehole trajectory line, a slurry diffusion diameter line, and a grouting depth line, wherein the slurry diffusion diameter line and the grouting depth line form the boundary line of the ratio grid line.

[0009] In some embodiments of the present invention, the grouting volume ratio line is drawn based on the ratio of the actual grouting volume to the designed grouting volume, and the pressure ratio line is drawn based on the ratio of the actual grouting pressure to the designed grouting pressure.

[0010] In some embodiments of the present invention, when the grouting volume ratio line is absent, or the pressure ratio line is absent, or both the grouting volume ratio line and the pressure ratio line fail to reach the boundary line of the ratio grid line, the grouting effect of the grouting section is evaluated as substandard; otherwise, the grouting effect of the grouting section is considered satisfactory.

[0011] In some embodiments of the present invention, grouting sections that do not meet the grouting effect are marked and supplementary grouting measures are taken.

[0012] In some embodiments of the present invention, plotting the pressure-to-volume ratio graph includes the following steps: Draw a correspondence diagram for a single grouting borehole, the correspondence diagram being consistent with the borehole grouting structure diagram; Plot the pressure ratio line and the grouting volume ratio line on the correspondence diagram to obtain the volume-pressure ratio diagram. Based on the evaluation results, mark the substandard grouting sections on the pressure-to-volume ratio chart.

[0013] In some embodiments of the present invention, when drawing the correspondence diagram of multiple adjacent grouting boreholes, the correspondence diagram of a single grouting borehole should be drawn separately, and the midpoint line of the distance between adjacent boreholes should be used as the grout diffusion diameter line. In some embodiments of the present invention, each grouting segment of a single grouting borehole is treated as a plotting unit, and each plotting unit is a pressure-to-volume ratio diagram.

[0014] In a second aspect of the invention, a system for evaluating the effectiveness of grouting for formation reinforcement based on a pressure-volume ratio diagram is provided, comprising: The grouting volume-pressure ratio diagram drawing module is configured to: acquire grouting data for each grouting segment, and draw a grouting volume-pressure ratio diagram for each grouting segment based on the grouting data; the grouting volume-pressure ratio diagram includes grouting volume ratio lines, pressure ratio lines, and ratio grid lines; The grouting effect evaluation module is configured to evaluate whether the grouting effect of each grouting section meets the standard based on whether the grouting volume ratio line reaches the left and right boundary lines of the ratio grid line and whether the pressure ratio line reaches the upper boundary line of the ratio grid line.

[0015] One or more technical solutions of the present invention have the following beneficial effects: (1) The present invention uses the drawn pressure-volume ratio diagram to evaluate the grouting reinforcement effect. The pressure-volume ratio diagram can organically combine the grouting pressure and the grouting volume, and display them graphically to evaluate the grouting effect of the borehole. It is a new method for evaluating the grouting effect. The diagram is simple and intuitive, easy to identify, and the grouting reinforcement effect of a certain section of a borehole can be quickly judged by the diagram.

[0016] (2) The present invention utilizes the pressure-volume ratio diagram to analyze and evaluate the grouting reinforcement effect on the surrounding rock in a single borehole, as well as the overall grouting reinforcement effect of multiple boreholes on a certain grouting section. Especially after the grouting of a large number of boreholes is completed, when analyzing the grouting effect of the entire grouting area, the intuitive advantage of the pressure-volume ratio diagram is prominent. It can quickly identify areas where the grouting is substandard and guide supplementary grouting reinforcement for these areas.

[0017] (3) The grouting borehole pressure ratio chart provided by this invention processes a large amount of complex borehole grouting data through calculation and displays it graphically. This frees professional technicians from the tedious and intensive work of analyzing and screening grouting data, eliminates errors that occurred in the previous analysis and screening of grouting effects, and makes the evaluation more intuitive and simple. It also fills the gap in the currently used methods for evaluating the grouting effect of surrounding rock.

[0018] (4) The grouting borehole pressure ratio diagram provided by the present invention includes not only the structural information of the evaluated grouting borehole, but also the relationship information between the final grouting pressure and the grouting volume and the corresponding design value. It realizes the direct acquisition of grouting information and grouting effect from the diagram, and has the advantages of being simple and intuitive. Attached Figure Description

[0019] Figure 1 A structural diagram of the pressure ratio for a single grouting borehole; Figure 2 A structural diagram showing the pressure ratio of adjacent grouting boreholes; Figure 3 Chart showing the pressure ratio of substandard grouting for Type 1; Figure 4 The diagram shows the pressure ratio for grouting to meet the standard for Type 2. Figure 5 The diagram shows the pressure ratio for grouting of type 3. Figure 6 Chart showing the pressure ratio for substandard grouting in Type 4; Figure 7 Chart showing the pressure ratio of substandard grouting for Type 5; Figure 8 This is a cross-sectional view of a single borehole grouting structure; Figure 9 A diagram showing the correspondence between the grouting structure diagrams for a single borehole; Figure 10 This is a cross-sectional view of the grouting structure of multiple adjacent boreholes; Figure 11 This is a diagram showing the correspondence between cross-sectional views of multiple adjacent borehole grouting structures. Figure 12(a) shows the ratio grid lines in the correspondence diagram of a single grouting borehole; Figure 12(b) shows the ratio grid lines in the diagram of the correspondence between multiple adjacent grouting boreholes; Figure 13(a) shows the pressure ratio of the first drawing unit for a single grouting borehole; Figure 13(b) shows the pressure ratio of all plotted units in a single grouting borehole; Figure 14(a) shows the pressure ratio of a single grouting borehole containing substandard grouting conditions; Figure 14(b) highlights the plotting unit containing the grouting pressure ratio diagram that does not meet the standard with shading; Figure 15(a) shows the pressure ratio of two grouting boreholes with substandard grouting conditions; Figure 15(b) highlights the plotted unit containing the pressure ratio of grouting failure in two boreholes with shading. Figure 16(a) shows the experimental grouting boreholes and the plan layout of the grouting boreholes in the embodiment; Figure 16(b) is a cross-sectional view of the drilling and grouting structure in the sixth column of the embodiment; Figure 17(a) shows the corresponding relationship of the cross-sectional view of the grouting structure in column 6; Figure 17(b) is a graph of the pressure ratio drawn in the first drawing unit of borehole Z6-1; Figure 18(a) shows the pressure ratio plotted in all 20 plotting cells of the 6th column boreholes; Figure 18(b) highlights the plotting units containing all substandard grouting pressure ratios with shading; The following are the key elements: 1. Grouting borehole number, 2. Borehole trajectory line, 3. Grout diffusion diameter line, 4. Ratio grid line, 5. Pressure ratio line, 6. Grouting volume ratio line, 7. Grouting volume ratio label, 8. Grouting section depth line, 9. Grouting section depth data, 10. Rectangular shaded diagram of pressure ratio line, 11. Pressure ratio label, 12. Midpoint line of spacing between adjacent boreholes, 13. Shaded drawing unit for substandard grouting, 14. Drawing unit, 15. Grouting section distance number. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Example 1 In a typical embodiment of the present invention, a method for evaluating the effect of grouting for formation reinforcement based on a pressure-volume ratio diagram is proposed, comprising the following steps: Acquire grouting data for each grouting section, and plot the volume-pressure ratio diagram for each grouting section based on the grouting data; the volume-pressure ratio diagram includes grouting volume ratio lines, pressure ratio lines, and ratio grid lines; The grouting effect of each grouting section is evaluated based on whether the grouting volume ratio line reaches the left and right boundary lines of the ratio grid line and whether the pressure ratio line reaches the upper boundary line of the ratio grid line.

[0022] Furthermore, the grouting data includes grouting volume, grouting pressure, borehole trajectory, grout diffusion diameter, and grouting depth.

[0023] Furthermore, the pressure-to-volume ratio graph also includes borehole trajectory lines, slurry diffusion diameter lines, and grouting depth lines, wherein the slurry diffusion diameter lines and grouting depth lines form the boundary lines of the ratio grid lines.

[0024] Furthermore, the grouting volume ratio line is drawn based on the ratio of the actual grouting volume to the designed grouting volume, and the pressure ratio line is drawn based on the ratio of the actual grouting pressure to the designed grouting pressure.

[0025] Specifically, the structure of a single borehole pressure-to-volume ratio chart, such as... Figure 1 As shown, the figure includes grouting borehole number 1 (K), borehole trajectory line 2, grout diffusion diameter line 3, ratio grid line 4, pressure ratio line 5, grouting volume ratio line 6, grouting volume ratio label 7 (En, n is a natural number), grouting depth line 8 (divided into upper and lower grouting depth lines), grouting section depth data 9 (including depth data hb corresponding to the upper grouting depth line and depth data hb+1 corresponding to the lower grouting depth line), and a rectangular shaded area for the pressure-volume ratio line. Figure 10 The pressure ratio is marked as 11 (Cn, where n is a natural number). Figure 1 This represents the pressure-volume ratio diagram within the grouting section (nth grouting section) at depths hb to hb+1 inside borehole K. The grout diffusion diameter lines 3 on either side of the grouting borehole trajectory line 2 are the boundary lines of the grout volume ratio line 6, while the upper grouting depth line corresponding to hb and the lower grouting depth line corresponding to hb+1 are the boundary lines of the pressure ratio line 5.

[0026] The structure of a pressure ratio diagram for multiple adjacent grouting boreholes, such as... Figure 2 As shown, in addition to possessing the structural features of a single borehole pressure-volume ratio diagram, the midpoint line 12 of the distance between adjacent boreholes on both sides of each borehole trajectory line replaces the grout diffusion diameter line 3 of a single borehole; the midpoint line 12 of the distance between adjacent boreholes on both sides of a certain grouting borehole trajectory line 2 serves as the boundary line of the grouting volume ratio line for that borehole. The pressure ratio line for a certain grouting section of a certain borehole is labeled with the borehole number minus the pressure ratio symbol for that grouting section (e.g., A0-Cn, Ar-Cn); similarly, the grouting volume ratio line for a certain grouting section of a certain borehole is labeled with the borehole number minus the grouting volume ratio symbol for that grouting section (e.g., A0-En, Ar-En). Pressure ratio and grouting volume ratio data can be found in the ratio data statistics table.

[0027] Specifically, based on different combinations of pressure ratio line lengths and grouting volume ratio line lengths and their respective meanings, pressure ratio charts of different shapes are classified to evaluate whether the grouting effect has reached the design value, i.e., whether it meets the standard.

[0028] The evaluation of grouting effect using the pressure-volume ratio chart includes the following five types: Type 1: The lengths of both the pressure ratio line and the grouting volume ratio line do not reach their boundary lines.

[0029] The pressure ratio chart of this type is as follows: Figure 3The actual grouting final pressure and grouting volume both failed to meet design requirements. This phenomenon may be caused by an abnormal situation occurring after the grouting process had continued for a certain period, forcing the grouting to stop. The evaluation result is that the grouting in this section of the borehole is substandard.

[0030] Type 2: The length of the pressure ratio line cannot fill its boundary line, but the length of the grouting volume ratio line reaches or exceeds its boundary line. The pressure ratio chart of this type is as follows: Figure 4 As shown, the final grouting pressure increased but did not reach the design value, while the grouting volume reached or exceeded the design volume. The analysis indicates that the grouting formation was loose with a high porosity and strong injectability. Even at relatively low grouting pressure, the grout diffused a long distance, indicating that the grout still filled the grouting formation despite the low pressure. In this case, because the grouting volume reached or exceeded the design volume, the evaluation result is that the grouting of this section of the borehole met the standards.

[0031] Type 3: The length of the pressure ratio line fills or exceeds its boundary line, but the length of the grouting volume ratio line does not reach its boundary line.

[0032] The pressure ratio chart of this type is as follows: Figure 5 As shown, this indicates that the final grouting pressure reached or exceeded the design value, but the grouting volume did not reach the design volume. The possible reason is that the surrounding rock of the stratum being grouted is relatively dense, with low porosity and poor injectability, making it difficult for the grout to diffuse. In this case, the final grouting pressure reaching or exceeding the design value is due to the properties of the surrounding rock, and the evaluation result is that the grouting meets the standards. The pressure-volume ratio diagram is shown below. Figure 5 The length of the grouting volume ratio line does not reach its boundary, but the length of the pressure ratio line reaches or exceeds its boundary.

[0033] Type 4: The length of the pressure ratio line is almost 0, but the length of the grouting volume ratio line reaches or exceeds its boundary.

[0034] The pressure ratio chart of this type is as follows: Figure 6 This indicates that the final grouting pressure is extremely low or zero, and the grouting volume far exceeds the design volume. This phenomenon likely indicates the existence of large voids within the formation that are difficult to fill over a long period, or that grout leakage occurred within a very short time after the grouting began. The evaluation result is that the grouting is substandard.

[0035] Type 5: The length of the grouting volume ratio line is almost 0, but the length of the pressure ratio line reaches or exceeds its boundary.

[0036] Pressure-to-volume ratio chart as shown Figure 7 The image shows a blockage in the grouting pipeline. One scenario is that at the beginning of grouting, with an extremely low grouting volume, the grouting pressure rapidly spikes to or exceeds the design value, such as... Figure 7 As shown in (a). Another case is as follows: Figure 7As shown in (b), after a certain period of grouting, the grouting pipeline suddenly became blocked, causing the grouting pressure to rise rapidly and suddenly, exceeding the design value. This was caused by the blockage of the grouting pipeline, and the evaluation result was that the grouting was substandard.

[0037] Drawing a pressure-to-volume ratio chart includes the following steps: Draw a correspondence diagram for a single grouting borehole, the correspondence diagram being consistent with the borehole grouting structure diagram; Plot the pressure ratio line and the grouting volume ratio line on the correspondence diagram to obtain the volume-pressure ratio diagram. Based on the evaluation results, mark the substandard grouting sections on the pressure-to-volume ratio chart.

[0038] Furthermore, when drawing the correspondence diagram of multiple adjacent grouting boreholes, the correspondence diagram of a single grouting borehole should be drawn separately, and the midpoint line of the distance between adjacent boreholes should be used as the grout diffusion diameter line.

[0039] Furthermore, each grouting section of a single grouting borehole is treated as a drawing unit, and each drawing unit is a pressure-to-volume ratio diagram.

[0040] Specifically, the drawing of the pressure-volume ratio chart includes the following steps: 1. Drawing the correspondence diagram The correspondence diagram is the basic diagram for drawing the quantity-pressure ratio diagram.

[0041] (1) Drawing of the correspondence diagram of a single grouting borehole like Figure 8 As shown, taking multi-segment grouting of a single borehole as an example, a cross-sectional view of the borehole grouting structure is first drawn. The cross-sectional view includes the borehole number K, borehole trajectory line 2, segmented grouting depths 9 (including top and bottom depths, such as h1~h3), grouting segment numbers and their lengths 15 (L1~L3), and grout diffusion diameter line 3 (D), etc. According to the theory of permeable grouting in loose surrounding rock, the grout diffuses outward at a constant speed and distance from the borehole, forming cylinders with diameter D and lengths L1, L2, and L3 respectively. Therefore, on the cross-section perpendicular to the borehole axis, the grout diffusion shape is a circle with diameter D centered on the borehole.

[0042] by Figure 9 For example, the correspondence diagram drawn is similar to the borehole grouting structure diagram. When drawing the correspondence diagram, borehole number 1, borehole trajectory line 2, grouting depth line 8, grouting depth data 9, grout diffusion diameter line 3, etc., all need to be matched with the individual borehole grouting structure. Figure 1 One-to-one correspondence.

[0043] In the single borehole grouting structure diagram, the depth line and grout diffusion diameter line are drawn to a certain scale based on actual data. However, in the correspondence diagram, the grouting depth line and grout diffusion diameter line do not need to be drawn to the same scale. To simplify the subsequent drawing of the pressure-to-volume ratio diagram, the distance between multiple adjacent grouting depth lines in the correspondence diagram is equal, and the spacing between them and the two grout diffusion diameter lines is also equal. Therefore, two adjacent grouting depth lines and two grout diffusion diameter lines enclose a square. This square is a drawing unit 14 for a pressure-to-volume ratio diagram.

[0044] (2) Drawing of the correspondence diagram of multiple adjacent boreholes by Figure 10 Taking two adjacent grouting boreholes as an example. For multiple adjacent boreholes (including 2), the grouting structure diagram consists of multiple borehole grouting structure cross-sectional diagrams, including borehole numbers (K1, K2), borehole trajectory lines, grout diffusion diameter D, borehole spacing A, the midpoint line of the borehole spacing 12, grouting depth data (h1, h2, h3, h4), the grouting depth lines corresponding to the grouting depth data, and grouting segment intervals (e.g., L1, L2, L3, etc.). Its structural cross-sectional diagram is similar to that of a single borehole grouting structure cross-sectional diagram, except that it is an accumulation of single borehole grouting structure cross-sectional diagrams.

[0045] When drawing the correspondence diagram of multiple adjacent grouting boreholes, it should be drawn separately as a single grouting borehole correspondence diagram, except that the midpoint line 12 of the distance between adjacent boreholes is used instead of the grout diffusion diameter line 3. The drawn correspondence diagram of multiple adjacent grouting boreholes is as follows: Figure 11 As shown.

[0046] 2. Drawing the pressure ratio line and the grouting volume ratio line.

[0047] (1) Drawing of ratio grid lines. Draw ratio grid lines 4 on the correspondence diagram. On the correspondence diagram of a single grouting borehole, take the two adjacent upper and lower grouting depth lines (h1 and h2 respectively) and the slurry diffusion diameter lines 3 on both sides of the borehole trajectory line as a drawing unit 14. One drawing unit represents a certain grouting section of a certain borehole. Draw ratio grid lines within the drawing unit. The ratio grid lines are 10 small squares in both the vertical and horizontal directions. The side length of each small square represents a ratio of 0.1. The vertical and horizontal spacing of the ratio grid lines drawn on the correspondence diagram of the same grouting borehole is equal. Because the distance between each pair of adjacent grouting depth lines on the correspondence diagram is equal, and it is also equal to the distance between the two slurry diffusion diameter lines, the ratio grid lines 4 are the same in all drawing units of a single grouting borehole, as shown in Figure 12(a).

[0048] The method for drawing the ratio grid line 4 on the correspondence diagram of multiple adjacent grouting boreholes is the same as that for drawing the correspondence diagram of a single grouting borehole, except that it is the sum of several correspondence diagrams of grouting boreholes. The drawing result is shown in Figure 12(b). In this figure, the drawing unit 14 marked with a thick solid line refers to the first grouting section of the grouting borehole numbered K1.

[0049] (2) Drawing of pressure ratio line. Taking Figure 13(a) as an example, in a drawing unit 14 of the grouting borehole numbered K, the position of pressure ratio line 5 coincides with the borehole trajectory line 2. Its lower end point is located at the intersection of the borehole trajectory line 2 and the lower grouting depth line (the line corresponding to grouting depth h2). Extending upward according to its ratio, the two depth lines above and below the drawing unit (i.e., the horizontal lines corresponding to grouting depth h1 and grouting depth h2) are the boundary lines of the pressure ratio line 5. The length of the pressure ratio line 5 is marked with the pressure ratio (C1), and the pressure ratio line is drawn with a thick solid line.

[0050] The pressure ratio (Cn) within the nth plotting unit of a grouting borehole is the ratio (Pn / P) between the actual final grouting pressure and the designed final grouting pressure of the nth grouting segment of the borehole. If multiple grouting operations were performed on this segment, the actual final pressure of this segment would be the average of the multiple final grouting pressures. When the actual final pressure equals the designed final pressure, i.e., Pn / P=1, the length of the pressure ratio line is the distance between the upper and lower grouting depth lines of this plotting unit, i.e., the length of the pressure ratio line reaches the upper grouting depth line. When the Pn / P, i.e., Cn value, exceeds or is less than 1, the length of the pressure ratio line is plotted according to the corresponding actual ratio. As shown in Figure 13(a), the pressure ratio is 11 (C1=Pn / P=1), so the length 5 of the pressure ratio line marked by the pressure ratio 11 (C1) occupies 10 ratio grids, and the upper endpoint reaches the intersection of the upper grouting depth line and the borehole trajectory line.

[0051] (3) Drawing the grouting ratio line. Taking Figure 13(a) as an example, in a drawing unit 14 of the grouting borehole numbered K, the grouting ratio line 6 coincides with the lower grouting depth line (the grouting depth line corresponding to h2) of the drawing unit. The midpoint of the grouting ratio line 6 is located at the intersection of the borehole trajectory line 2 and the lower grouting depth line. The grout diffusion diameter line 3 on both sides of the borehole is used as the boundary line of the grouting ratio line 6. The grouting ratio line 6 is drawn with a thick solid line, and the length of the grouting ratio line 6 is marked with the corresponding grouting ratio 7 (E1).

[0052] The grouting ratio (En) within the nth plotting unit of a grouting borehole is the ratio (Qn / q) between the total grouting volume and the design volume for that grouting section of the borehole. The length of the grouting ratio line is also plotted according to this ratio. When the actual total grouting volume of the grouting section is equal to the design grouting volume, i.e., En = Qn / q = 1, the grouting ratio line 5 corresponding to the grouting ratio (En) reaches its boundary line at both ends; when the value of En = Qn / q is less than 1 or greater than 1, it is plotted according to the actual ratio. In Figure 13(a), the grouting ratio (E1) is 0.6, and the length of the grouting ratio line marked by this grouting ratio E1 occupies 6 ratio grids.

[0053] Using the method described above, the pressure ratio line and grouting volume ratio line for each plotting unit of a single grouting borehole can be drawn, as shown in Figure 13(b).

[0054] (4) Drawing of pressure ratio lines and grouting volume ratio lines of multiple adjacent grouting boreholes under abnormal conditions. When the pressure ratio or grouting volume ratio is greater than 1, the length of the corresponding ratio line should exceed its boundary line and be drawn according to the actual ratio. In order to prevent the pressure ratio lines or grouting volume ratio lines of adjacent drawing units from overlapping and affecting the analysis and judgment of their types, the ratio lines with ratios exceeding 1 are offset from their overlapping lines by a certain distance (i.e., the pressure ratio lines are offset from the borehole trajectory lines or the grouting volume ratio lines are offset from the lower grouting depth lines). See the pressure ratio line marked K2-C3 and the grouting volume ratio line marked K2-E4 in Figure 15(a).

[0055] (5) Shaded rectangle of pressure ratio line Figure 10 Rectangles are drawn with the lengths of the pressure ratio line and the grouting volume ratio line as their sides, and the grouting volume ratio line as its base. The rectangles are then filled with shading. This shading rectangle is the shading diagram of the pressure ratio line. See label 10 in Figures 13(a) and 13(b).

[0056] Application of pressure-volume ratio chart in evaluating borehole grouting effectiveness: When the grouting volume ratio line or the pressure ratio line is absent, or when neither the grouting volume ratio line nor the pressure ratio line reaches the boundary line of the ratio grid line, the grouting effect of the grouting section is evaluated as substandard; otherwise, the grouting effect of the grouting section is considered satisfactory. Grouting sections with substandard grouting effects are marked, and supplementary grouting measures are taken.

[0057] Specifically, the evaluation of the grouting effect of a single borehole is based on the type of pressure-volume ratio diagram. Taking Figure 14(a) as an example, the grouting borehole K is divided into four grouting sections: h2-h1, h3-h2, h4-h3, and h5-h4. According to the classification of the pressure-volume ratio diagram, the pressure-volume ratio diagram of section h3-h2 belongs to type 1, which is a substandard grouting section; the pressure-volume ratio diagram of section h4-h3 belongs to type 6, which is a substandard grouting section; the pressure-volume ratio diagram of section h2-h1 belongs to type 3, which is a standard grouting section; and the pressure-volume ratio diagram of section h5-h4 belongs to type 2, which is a standard grouting section. To highlight the substandard sections, the drawing units of the substandard grouting sections are filled with a gray-black shadow. This shadow is called the substandard grouting display shadow diagram 13, as shown in Figure 14(b). This will clearly show the grouting sections where the grouting is substandard on the pressure-volume ratio chart. The accurate display of substandard sections in the borehole can provide guidance for comprehensively evaluating the grouting effect and taking supplementary grouting measures for the substandard sections.

[0058] The application principle of the pressure ratio chart for multiple adjacent grouting boreholes is the same as that for a single grouting borehole. See Figures 15(a) and 15(b).

[0059] The following is a detailed explanation using a deep foundation pit in Jinan City, specifically a deep-buried foundation pit for a comprehensive utility tunnel. During the excavation of this foundation pit, concentrated water inflow occurred in some areas. Due to the large volume of water, continued excavation was impossible, forcing the project to stop. The foundation pit was then backfilled with slag. After backfilling, grouting treatment was carried out on the deep foundation pit. The treatment plan involved sealing the aquifer at the bottom of the foundation pit, grouting the surrounding soil and rock to plug water, and grouting to reinforce and strengthen it. A segmented grouting method using boreholes was adopted.

[0060] To obtain the hydrogeological conditions of the water-bearing section of the foundation pit, and to determine safe grouting parameters such as the final grouting pressure and the grouting volume per hole and section, preliminary geological exploration and grouting tests were necessary. Four boreholes (S1–S4 in Figure 16(a)) were designed and constructed for geological exploration and grouting test purposes. The exploration revealed that the strata, from top to bottom, consisted of fill, slag fill, silty clay, silt, and gravel layers, with the gravel layer being the aquifer. Due to human disturbance or natural causes, a water-conducting channel was created between the foundation pit and the aquifer, allowing water from the gravel layer to enter the excavation face of the foundation pit and cause water inflow. The grouting test involved drilling into the gravel layer according to the strata properties and the needs of grouting reinforcement. Grouting was performed to plug the water in the gravel layer, sealing the water-conducting channel between the gravel layer and the bottom of the foundation pit, and reinforcing the loose strata through grouting. Through grouting tests, the safe final grouting pressure and grouting volume for grouting water plugging and grouting reinforcement of the stratum were basically obtained. These safe final grouting pressure and grouting volume, as the design values ​​of the grouting parameters for the entire water inflow area of ​​the foundation pit, can be used as evaluation indicators to measure whether the subsequent grouting reinforcement effect meets the standards. The distribution of the grouting test boreholes is shown in Figure 16(a) (S1~S4).

[0061] As shown in Figure 16(a), based on the results of four exploratory and grouting test boreholes, the main grouting techniques determined for the entire water-inflow section of the foundation pit are as follows: (1) Arrangement and grouting structure of grouting boreholes. As shown in Figure 16(a), a total of 31 grouting boreholes were designed for the treatment of deep foundation pits, arranged in 7 columns. The boreholes were numbered by column (e.g., Z6-1, Z6-2, etc.), with a column spacing of 3m and a spacing of 4m between adjacent boreholes in the same column. The boreholes between adjacent columns were arranged in a triangular pattern. As shown in Figure 16(b), the grouting structure is shown in the cross-sectional view. The 0-5m section is the non-grouting section, with a grouting depth of 33m. The grouting is divided into 4 sections within the 5m to 33m range, with grouting depths and section spacings of 5-11 / 6m (L1 section), 11-17 / 6m (L2 section), 17-24 / 7m (L3 section), and 24-33 / 9m (L4 section).

[0062] (2) Design grouting parameters. Based on the geological properties at different depths, the pressurized incremental grouting process is adopted. That is, as the grouting depth increases, the design final grouting pressure and grouting volume both show an increasing trend. The design final grouting pressure and design grouting volume at different depth intervals obtained through grouting tests are shown in Table 1.

[0063] Table 1. Statistical table of grouting parameters for boreholes at different depth intervals.

[0064] Taking the grouting borehole in column 6 of Figure 16(a) as an example, this paper introduces the method for drawing the pressure-volume ratio diagram and evaluating its effect on grouting. Table 1 shows the statistical data of the actual final grouting pressure and grouting volume for each section in the five grouting boreholes in column 6. Figure 16(b) shows the cross-sectional view of the grouting structure of the borehole in column 6.

[0065] For ease of drawing, the markings of pressure ratio and grouting volume ratio in the pressure-volume ratio diagram are simplified. In the pressure-volume ratio diagram, borehole numbers Z6-1 to Z6-5 are replaced with K1 to K5 respectively.

[0066] (1) First, draw the corresponding relationship diagram based on the cross-sectional view of the borehole grouting structure in Figure 16(b).

[0067] Draw the borehole trajectory lines 2 for 5 boreholes, and label them sequentially as borehole number 1, grouting depth data 9, grouting depth line 8, midpoint line of distance between adjacent boreholes 12, etc. The correspondence diagram is shown in Figure 17(a).

[0068] (2) Start drawing the pressure ratio diagram of the first drawing unit 14 of the first grouting section (5m-11m section) of the Z6-1 (K1) borehole.

[0069] First, draw the ratio grid line 4. Draw the ratio grid line 4 according to the drawing unit having 10 small squares in each direction.

[0070] As shown in Figure 17(b), the pressure-to-volume ratio diagram is drawn in the first drawing unit (i.e., the grouting section of borehole Z6-1, 5-11m).

[0071] From Table 1, we can find that the grouting volume ratio for the 5-11m section of borehole Z6-1 is 0.58, and the pressure ratio is 1.12. Coinciding with the grouting depth line corresponding to 11m, and centering on the intersection of borehole trajectory line 2 (Z6-1) and this grouting depth line, we draw grouting volume ratio line 6. This line occupies 5.8 ratio grids and is displayed in thicker form. This grouting volume ratio line is labeled with grouting volume ratios K1-E1. Using the intersection of borehole trajectory line 2 (Z6-1) and the 11m grouting depth line as the endpoint, and coinciding with borehole trajectory line 2, we draw pressure ratio line 5 upwards. This line occupies 11.2 ratio grids and is drawn with a thick solid line. This pressure ratio line is labeled with K1-C1. Using the grouting volume ratio line 6 as the base and the length of the grouting volume ratio line 6 and the length of the pressure ratio line 5 as the side lengths, draw a rectangular shaded area for the grouting volume ratio line. Figure 10 The pressure-to-volume ratio diagram for the first grouting section of borehole Z6-1 has been completed.

[0072] Similarly, following the above method, the pressure ratio diagrams of a total of 20 plotting units for all 5 grouting boreholes can be drawn, as shown in Figure 18(a).

[0073] (3) Compare the types of pressure-volume ratio charts, determine the sections where grouting is substandard, and highlight them. Based on the notes in Table 1 and the different types of ratio diagrams within the 20 plotting units of the 6 boreholes, all substandard grouting sections identified according to the pressure-volume ratio diagram type in Figure 18(a) are filled with gray-black shading, resulting in the gray-black shading diagram of substandard grouting sections shown in Figure 18(b). Figure 18(b) clearly shows that 5 grouting sections from 4 boreholes are substandard.

[0074] Based on the indications and guidance provided in Figure 18(b) regarding the substandard grouting sections, supplementary grouting was carried out on sections 11-24m of borehole Z6-1, 5-11m of borehole Z6-2, 24-33m of borehole Z6-4, and 11-17m of borehole Z6-5. This eliminated the potential for ground water inrush caused by substandard grouting, successfully sealed the water in the pebble layer, and reinforced other strata with grouting. The overall grouting effect was good, meeting the safety technical requirements for the re-excavation of the foundation pit.

[0075] Example 2 In another typical embodiment of the present invention, a formation reinforcement grouting effect evaluation system based on the pressure-volume ratio diagram is proposed, characterized in that it includes: The grouting volume-pressure ratio diagram drawing module is configured to: acquire grouting data for each grouting segment, and draw a grouting volume-pressure ratio diagram for each grouting segment based on the grouting data; the grouting volume-pressure ratio diagram includes grouting volume ratio lines, pressure ratio lines, and ratio grid lines; Based on the positional relationship between the grouting volume ratio line and the pressure ratio line and the boundary line of the ratio grid line, the grouting effect of each grouting section is evaluated to determine whether it meets the standards.

[0076] The grouting effect evaluation module is configured to evaluate whether the grouting effect of each grouting section meets the standard based on whether the grouting volume ratio line reaches the left and right boundary lines of the ratio grid line and whether the pressure ratio line reaches the upper boundary line of the ratio grid line.

[0077] The embodiments described above provide a detailed explanation of the technical solution of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the effect of grouting for formation reinforcement based on a pressure-volume ratio diagram, characterized in that, Includes the following steps: Acquire grouting data for each grouting section, including grouting volume, grouting pressure, grout diffusion diameter, and grouting depth. Based on the grouting data, plot a volume-pressure ratio diagram for each grouting section. The volume-pressure ratio diagram includes a grouting volume ratio line, a pressure ratio line, and a ratio grid line. The pressure-to-volume ratio chart also includes a borehole trajectory line, a slurry diffusion diameter line, and a grouting depth line, wherein the slurry diffusion diameter line and the grouting depth line form the boundary line of the ratio grid line; The grouting effect of each grouting section is evaluated based on whether the grouting volume ratio line reaches the left and right boundary lines of the ratio grid line and whether the pressure ratio line reaches the upper boundary line of the ratio grid line. When the grouting volume ratio line or the pressure ratio line does not exist, or when neither the grouting volume ratio line nor the pressure ratio line reaches the boundary line of the ratio grid line, the grouting effect of the grouting section is evaluated as substandard; otherwise, the grouting effect of the grouting section is evaluated as satisfactory. Mark the grouting sections where the grouting effect is not up to standard, and take supplementary grouting measures; Draw a correspondence diagram for a single grouting borehole. Each grouting section of a single grouting borehole is a drawing unit, and each drawing unit is a pressure-to-volume ratio diagram.

2. The method for evaluating the grouting effect of formation reinforcement based on the pressure-volume ratio diagram as described in claim 1, characterized in that, The grouting volume ratio line is drawn based on the ratio of the actual grouting volume to the designed grouting volume, and the pressure ratio line is drawn based on the ratio of the actual final grouting pressure to the designed final grouting pressure.

3. The method for evaluating the grouting effect of formation reinforcement based on the pressure-volume ratio diagram as described in claim 1, characterized in that, Drawing a pressure-to-volume ratio chart includes the following steps: Draw a correspondence diagram for a single grouting borehole, the correspondence diagram being consistent with the borehole grouting structure diagram; Plot the pressure ratio line and the grouting volume ratio line on the correspondence diagram to obtain the volume-pressure ratio diagram; Based on the evaluation results, mark the substandard grouting sections on the pressure-to-volume ratio chart.

4. The method for evaluating the grouting effect of formation reinforcement based on the pressure-volume ratio diagram as described in claim 3, characterized in that, When drawing the correspondence diagram of multiple adjacent grouting boreholes, the correspondence diagram of a single grouting borehole should be drawn separately, and the midpoint line of the distance between adjacent boreholes should be used instead of the grout diffusion diameter line.

5. A system for evaluating the effect of grouting for formation reinforcement based on a pressure-volume ratio diagram, characterized in that, The method for evaluating the grouting effect of formation reinforcement based on the pressure-volume ratio diagram as described in any one of claims 1-4 includes: The volume-pressure ratio diagram drawing module is configured to: acquire grouting data for each grouting segment, the grouting data including grouting volume, grouting pressure, grout diffusion diameter, and grouting depth; and draw a volume-pressure ratio diagram for each grouting segment based on the grouting data; the volume-pressure ratio diagram includes a grouting volume ratio line, a pressure ratio line, and a ratio grid line; the volume-pressure ratio diagram also includes a borehole trajectory line, a grout diffusion diameter line, and a grouting depth line, wherein the grout diffusion diameter line and the grouting depth line form the boundary line of the ratio grid line; The grouting effect evaluation module is configured to: evaluate whether the grouting effect of each grouting segment meets the standard based on whether the grouting volume ratio line reaches the left and right boundary lines of the ratio grid line and whether the pressure ratio line reaches the upper boundary line of the ratio grid line; when the grouting volume ratio line or the pressure ratio line does not exist, or when neither the grouting volume ratio line nor the pressure ratio line reaches the boundary line of the ratio grid line, the grouting effect of the grouting segment is evaluated as substandard; otherwise, the grouting effect of the grouting segment is considered satisfactory; grouting segments with substandard grouting effects are marked and supplementary grouting measures are taken; a correspondence diagram of a single grouting borehole is drawn, with each grouting segment of a single grouting borehole as a drawing unit, and each drawing unit is a volume-pressure ratio diagram.

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