A multi-capsule pipe grouting arrangement method for controlling uniform lifting of a roadbed

Abstract

This invention belongs to the field of geotechnical engineering and roadbed treatment technology, and discloses a method for grouting arrangement of multi-bladder tubes to control uniform roadbed uplift. The method includes the following steps: establishing a vertical additional stress model for elastic semi-infinite soil caused by a single bladder tube and a calculation model for roadbed surface uplift displacement, and performing dimensionless processing; determining the zero point of conversion between compressive and tensile stress at different depths through dimensionless analysis, and plotting a dimensionless zero vertical additional stress envelope curve; based on this, proposing a zero-overlap design criterion: the ratio of the spacing L between adjacent bladder tubes to the burial depth H must be ≤0.84 to avoid overlap of tensile stress zones; optimizing the spacing and burial depth ratio of the bladder tubes according to the zero-overlap design criterion to eliminate uneven uplift with peaks and troughs in the roadbed surface uplift displacement curve. The advantages of this invention are: revealing the distribution characteristics of zero vertical additional stress in semi-infinite soil, providing a theoretical basis for bladder tube spacing design; and providing quantitative guidance for engineering layout, avoiding wavy uplift.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering and roadbed treatment technology, specifically relating to a multi-bladder grouting arrangement method for controlling the uniform uplift of the roadbed. Background Technology

[0002] In existing railway and highway subgrade reinforcement projects, grouting bladder (single-bladder / multi-bladder) technology is widely used due to its advantages such as good controllability and minimal disturbance.

[0003] However, traditional single-tube grouting can cause the roadbed surface to rise and displace in a Gaussian pattern, resulting in localized uplifts. When multiple tubes are used for combined grouting, if they are not arranged properly, the uplift waves generated by each tube will overlap, forming a wave-like uneven uplift with peaks and troughs, which seriously affects the smoothness of the road surface and driving safety.

[0004] Existing technologies lack quantitative design criteria for the relationship between the spacing between the tubes and the burial depth, making it difficult to fundamentally eliminate the problem of uneven lifting caused by tensile stress zones. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a multi-bladder grouting arrangement method for controlling the uniform rise of the roadbed. By establishing a zero vertical additional stress envelope curve and proposing a "zero overlap design criterion," the overlapping of tensile stress zones of adjacent bladders is avoided, thereby achieving a flat and uniform rise of the roadbed surface.

[0006] The objective of this invention is achieved through the following technical solutions: A method for grouting multi-bladder tubes to control uniform uplift of roadbed includes the following steps: S1: Establish a vertical additional stress model for the elastic semi-infinite soil caused by a single bladder tube and a calculation model for the surface uplift displacement of the roadbed, and perform dimensionless processing. The vertical additional stress model for the elastic semi-infinite soil and the calculation model for the surface uplift displacement of the roadbed are as follows:

[0007]

[0008] In the formula: σ zz The vertical additional stress in a rectangular coordinate system is expressed in Pascals. u z ( x,0 () represents the surface uplift displacement of the roadbed in a rectangular coordinate system, in meters; p The grouting pressure in the bladder tube is expressed in Pascals. HThe depth of the borehole for arranging the bladder tubes is measured in meters. r The radius of the borehole is given in meters. x The lateral distance from the desired point to the center of the borehole is in meters. z The vertical depth from the point in question to the roadbed surface is expressed in meters. ξ The x-coordinate value of any point on the roadbed surface of the reference plane; E This is the elastic modulus of soil, measured in Pascals. μ Poisson's ratio of the soil mass is dimensionless. x m For the first m The root of the cystic duct in x The horizontal position coordinates on the axis, in meters. m ∈1, 2, 3, ... n ; n The total number of the cysts; The method for dimensionless processing is as follows:

[0009]

[0010] In the formula: The horizontal distance is dimensionless. The vertical depth is dimensionless. The radius of the dimensionless borehole; This refers to the dimensionless surface uplift displacement of the roadbed. The dimensionless distance between adjacent cystic ducts; The grouting pressure for the dimensionless bladder tube; This is a dimensionless vertical additional stress; S2: Calculate dimensionless vertical depths Additional vertical stress along the horizontal direction Distribution, determining the dimensionless vertical additional compressive stress The zero point of the transition with tensile stress; S3: Based on dimensionless depths At the zero point location, a dimensionless zero vertical additional stress envelope curve is plotted using interpolation. The boundary between the compression zone and the tension zone of the soil is defined by the dimensionless zero vertical additional stress envelope curve. S4: Based on the dimensionless zero vertical additional stress envelope curve, determine the zero overlap design criterion for the arrangement of multi-bladder tubes: the ratio of the distance L between adjacent bladder tubes to the burial depth H is less than or equal to a preset threshold, so as to avoid the tensile stress zones generated by adjacent bladder tubes from overlapping each other. S5: Based on the zero-overlap design criterion, optimize the spacing and burial depth ratio of the tubes to eliminate uneven uplift in the roadbed surface uplift displacement curve, such as peaks and troughs.

[0011] In step S3, based on the dimensionless different depths The zero-point location mentioned above, when plotted using interpolation to obtain the dimensionless zero vertical additional stress envelope curve, refers to: when =0, hour, It is 0.425; when =0, hour, It is 0.422; when =0, hour, It is 0.404; when =0, hour, It is 0.367; when =0, hour, It is 0.309; when =0, hour, It is 0.228; when =0, hour, It is 0.122.

[0012] In step S4, the preset threshold is 0.84.

[0013] The advantages of this invention are: (1) It reveals the distribution characteristics of zero vertical additional stress in semi-infinite soil, providing a theoretical basis for the design of the spacing between the capsule tubes; (2) The “zero overlap design criterion” (L / H ≤ 0.84) is proposed to provide quantitative guidance for the engineering layout and avoid wave-shaped elevation; (3) It can achieve a large-scale and highly uniform lifting of the roadbed surface, significantly improving the smoothness of the road surface; (4) Applicable to rapid correction of existing lines. Attached Figure Description

[0014] Figure 1 A schematic diagram of the Gaussian distribution of displacement on the roadbed surface lifted by a single bladder tube; Figure 2 A schematic diagram illustrating the peaks and troughs generated by the superposition of multiple cystic tube waves; Figure 3 For dimensionless different depths in this invention ( and The vertical additional stress along the lower edge Direction change curve (including zero point of compression-tension conversion); Figure 4 This is the dimensionless compression-tension conversion zero vertical additional stress envelope curve in this invention; Figure 5 This is the superposition result of the multi-cyst tube lifting displacement (uniform lifting) when the zero overlap criterion is met (L / H ≤ 0.84) in this invention. Figure 6 This is the dimensionless compression-tension conversion zero vertical additional stress envelope curve of the multi-cyst tube when the zero overlap criterion is met (L / H ≤ 0.84) in this invention; Figure 7 This is the result of superimposed displacement of the multi-cystic tubes when the zero overlap criterion is not met (L / H > 0.84) (lifting wave pattern). Figure 8 This is the dimensionless compression-tension conversion zero vertical additional stress envelope curve of the multi-cyst tube when the zero overlap criterion is not met (L / H > 0.84) in this invention; Figure 9 This is a comparison table of engineering verification cases in this invention. Detailed Implementation

[0015] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art: Example: Figures 1-9 As shown, this embodiment provides a multi-bladder grouting arrangement method for controlling the uniform uplift of the roadbed, addressing the issue of Gaussian bulges on the roadbed surface caused by existing single-bladder grouting methods (such as...). Figure 1 As shown), the multicystic ducts exhibit uneven, wave-like elevation due to improper spacing (e.g., Figure 2To address the problem (as shown), this embodiment, based on the theory of elastic semi-infinite bodies, establishes a model of vertical additional stress in the soil caused by a single bladder tube. Dimensionless analysis is used to determine the zero-point conversion between compressive and tensile stresses at different depths, and a dimensionless zero-vertical additional stress envelope curve is plotted. Based on this, a "zero-overlap design criterion" is proposed: the ratio of the distance L between adjacent bladder tubes to the burial depth H must satisfy L / H ≤ 0.84 to avoid overlapping of tensile stress zones. Verification using multi-bladder tube displacement superposition shows that when this criterion is met, the roadbed surface uplift curve is a broad, gentle platform with uniform uplift; when it is not met, it exhibits a wavy characteristic. Engineering examples verify the effectiveness of this criterion.

[0016] The multi-bladder grouting arrangement method for controlling the uniform uplift of the roadbed in this embodiment specifically includes the following steps: (S1) As Figure 1 As shown, a vertical additional stress model for elastic semi-infinite soil caused by a single bladder tube and a calculation model for the surface uplift displacement of the roadbed are established and dimensionless. The vertical additional stress model for elastic semi-infinite soil and the calculation model for the surface uplift displacement of the roadbed are as follows:

[0017]

[0018] In the formula: σ zz The vertical additional stress in a rectangular coordinate system is expressed in Pascals. u z ( x,0 () represents the surface uplift displacement of the roadbed in a rectangular coordinate system, in meters; p The grouting pressure in the bladder tube is expressed in Pascals. H The borehole depth for the arrangement of the bladder tubes, in meters; r The radius of the borehole is in meters. x The lateral distance from the point in question to the center of the borehole is in meters. z The vertical depth from the point in question to the roadbed surface is expressed in meters. ξ The x-coordinate value of any point on the roadbed surface of the reference plane; E This is the elastic modulus of soil, measured in Pascals. μ Poisson's ratio of the soil mass is dimensionless. x m For the firstm Root canal in x The horizontal position coordinates on the axis, in meters. m ∈1, 2, 3, ... n ; n This represents the total number of cysts.

[0019] The dimensionless processing method is as follows:

[0020]

[0021] In the formula: The horizontal distance is dimensionless. The vertical depth is dimensionless. The radius of the dimensionless borehole; This refers to the dimensionless surface uplift displacement of the roadbed. The dimensionless distance between adjacent cystic ducts; The grouting pressure for the dimensionless bladder tube; It is a dimensionless vertical additional stress.

[0022] (S2) Calculate dimensionless vertical depths Additional vertical stress along the horizontal direction Distribution, determining the dimensionless vertical additional compressive stress The zero point of the transformation with tensile stress, the zero point is... =0.

[0023] (S3) Based on dimensionless different depths At the zero point, a dimensionless zero vertical additional stress envelope curve is plotted using interpolation. The boundary between the compression zone and the tension zone of the soil is defined by the dimensionless zero vertical additional stress envelope curve.

[0024] According to dimensionless different depths At the zero point, the dimensionless zero vertical additional stress envelope curve plotted by interpolation refers to: when =0, hour, It is 0.425; when =0, hour, It is 0.422; when =0, hour, It is 0.404; when =0, hour, It is 0.367; when =0, hour, It is 0.309; when =0, hour, It is 0.228; when =0, hour, It is 0.122.

[0025] like Figure 3 As shown in the figure, the graph illustrates the dimensionless depth. and dimensionless depth Lower vertical additional stress along The curve of directional change (including the zero point of compression-tension conversion); such as Figure 4 As shown in the figure, the graph displays the dimensionless compression-tension conversion zero vertical additional stress envelope curve, which reveals that at the dimensionless depth... and dimensionless depth Within the area between them, the boundary between the compression zone and the tension zone of the soil is defined.

[0026] The compression zone and tension zone of soil are defined by the following formula: The soil mass is under overall pressure; The soil as a whole is under tension.

[0027] (S4) Based on the dimensionless zero vertical additional stress envelope curve, the zero-overlap design criterion for the multi-capsule arrangement is determined: the ratio of the distance L between adjacent capsules to the burial depth H is less than or equal to a preset threshold, i.e. This is to avoid the tensile stress zones generated by adjacent cysts overlapping each other.

[0028] (S5) The lifting effect was verified by using the superposition formula of surface displacement and lifting of multi-bladder pipe roadbed: When L / H ≤ 0.84, the combined lift displacement curve of the multi-cystic tube is a broad and gentle plateau; When L / H > 0.84, the displacement curve exhibits a wavy characteristic.

[0029] Based on the zero-overlap design principle, the spacing and burial depth ratio of the tubes are optimized to eliminate uneven uplift in the roadbed surface displacement curve, which is characterized by peaks and troughs.

[0030] like Figure 5As shown, this is the result of the superposition of the multi-cystic tube lifting displacement (uniform lifting) when the zero overlap criterion is met (L / H=5 / 6 is less than the preset threshold 0.84). like Figure 6 As shown, the dimensionless compression-tension conversion zero vertical additional stress envelope curve of the multi-cyst tube is obtained when the zero overlap criterion is met (L / H=5 / 6 is less than the preset threshold 0.84).

[0031] like Figure 7 As shown, this is the result of the superposition of the uplift displacement of the multicystic tube when the zero overlap criterion is not met (L / H=5 / 4 is greater than the preset threshold of 0.84) (uplift wave-like shape). like Figure 8 As shown, this is the dimensionless compression-tension conversion zero vertical additional stress envelope curve of the multi-cystic tube when the zero overlap criterion is not met (L / H=5 / 4 is greater than the preset threshold of 0.84).

[0032] In this embodiment, the multi-bladder grouting arrangement method for controlling the uniform lifting of the subgrade uses a grouting bladder subgrade lifting system. The system includes grouting bladders, grouting equipment, and a control unit. The number of grouting bladders is multiple and they are arranged in the subgrade according to the zero-overlap design principle. The grouting equipment is used to inject grout into each bladder to generate lifting force. The control unit calculates and controls the spacing, burial depth, and grouting sequence of the bladders according to the zero-overlap design principle to ensure uniform lifting of the subgrade surface.

[0033] like Figure 9 As shown, the data on the surface uplift displacement curves of the roadbed from multiple engineering cases are presented: Case Study 1: A subgrade uplift project for an existing railway, with a designed burial depth H = 1.5 meters. Based on the zero-overlap design criterion, L / H = 0.813 was used, and the calculated spacing between the grouting tubes L = 1.22 meters. A total of 9 grouting tubes were installed. After grouting, the subgrade surface uplift displacement curve was smooth and continuous, without any localized waves or sharp bulges, verifying the effectiveness of the invention.

[0034] Engineering Case 2: For comparison, non-optimal parameters were used: H = 1.0 meter, L = 1.22 meter. In this case, L / H = 1.22 > 0.84. Field experiments showed a distinct wavy uplift pattern on the roadbed surface (e.g., ...). Figure 7 As shown in the upper right corner, it is in high agreement with the theoretical prediction results of this invention, confirming the uneven lifting caused by the overlap of tensile stress zones when the zero overlap criterion is not met.

[0035] Project Case 3: Shallow Burial High Density Scheme: H=1.0 m, L=0.7 m, L / H=0.7 (meets the criteria) - suitable for areas with limited space but requiring uniform elevation.

[0036] Project Case 4: Deep Burial with Large Spacing: H=1.5 meters, L=1.8 meters, L / H=1.2 (does not meet the criteria) - only for temporary projects that allow for a certain degree of undulation or do not require uniform elevation.

[0037] In actual construction, first, based on the design burial depth H, select the spacing L according to L ≤ 0.84×H, and then determine the number of grout tubes according to the total lifting requirements. During grouting, a symmetrical, synchronous, or sequential grouting strategy should be adopted to avoid eccentric pressure.

[0038] The beneficial effects of this embodiment are: (1) It reveals the distribution characteristics of zero vertical additional stress in semi-infinite soil, providing a theoretical basis for the design of the spacing between the capsule tubes; (2) The “zero overlap design criterion” (L / H ≤ 0.84) is proposed to provide quantitative guidance for the engineering layout and avoid wave-shaped elevation; (3) It can achieve a large-scale and highly uniform lifting of the roadbed surface, significantly improving the smoothness of the road surface; (4) Applicable to rapid correction of existing lines.

Claims

1. A method for grouting multi-cell tubes to control uniform uplift of roadbed, characterized in that... The arrangement method includes the following steps: S1: Based on the grouting pressure of the bladder tube p The borehole depth for the arrangement of the supply tubes H Drilling radius r The lateral distance from the point to the borehole center x The vertical depth from the point to the roadbed surface z Soil elastic modulus E and Poisson's ratio of soil μ A vertical additional stress model for elastic semi-infinite soil induced by a single cyst tube and a calculation model for the surface uplift displacement of the roadbed were established and dimensionlessized to obtain the dimensionless horizontal distance. Dimensionless vertical depth Dimensionless borehole radius Dimensionless roadbed surface uplift displacement Dimensionless spacing between adjacent cystic ducts Dimensionless bladder grouting pressure Dimensionless vertical additional stress ; S2: Calculate dimensionless vertical depths Additional vertical stress along the horizontal direction Distribution, determining the dimensionless vertical additional compressive stress The zero point of the transition with tensile stress; S3: Based on dimensionless depths At the zero point location, a dimensionless zero vertical additional stress envelope curve is plotted using interpolation. The boundary between the compression zone and the tension zone of the soil is defined by the dimensionless zero vertical additional stress envelope curve. S4: Based on the dimensionless zero vertical additional stress envelope curve, determine the zero overlap design criterion for the arrangement of multi-bladder tubes: the ratio of the distance L between adjacent bladder tubes to the burial depth H is less than or equal to a preset threshold, so as to avoid the tensile stress zones generated by adjacent bladder tubes from overlapping each other. S5: Based on the zero-overlap design criterion, optimize the spacing and burial depth ratio of the tubes to eliminate uneven uplift in the roadbed surface uplift displacement curve, such as peaks and troughs.

2. The method for grouting multiple tubes to control uniform elevation of roadbed according to claim 1, characterized in that... The vertical additional stress model for the elastic semi-infinite soil and the calculation model for the surface uplift displacement of the roadbed are respectively: In the formula: σ zz The vertical additional stress in a rectangular coordinate system is expressed in Pascals. u z ( x,0 () represents the surface uplift displacement of the roadbed in a rectangular coordinate system, in meters; p The grouting pressure in the bladder tube is expressed in Pascals. H The depth of the borehole for arranging the bladder tubes is measured in meters. r The radius of the borehole is given in meters. x The lateral distance from the desired point to the center of the borehole is in meters. z The vertical depth from the point in question to the roadbed surface is expressed in meters. ξ The x-coordinate value of any point on the roadbed surface of the reference plane; E This is the elastic modulus of soil, measured in Pascals. μ Poisson's ratio of the soil mass is dimensionless. x m For the first m The root of the cystic duct in x The horizontal position coordinates on the axis, in meters. m ∈1, 2, 3, ... n ; n The total number of the cysts.

3. The method for grouting multiple bladder tubes to control uniform elevation of roadbed according to claim 2, characterized in that... The method for dimensionless processing is as follows: In the formula: The horizontal distance is dimensionless. The vertical depth is dimensionless. The radius of the dimensionless borehole; This refers to the dimensionless surface uplift displacement of the roadbed. The dimensionless distance between adjacent cystic ducts; The grouting pressure for the dimensionless bladder tube; It is a dimensionless vertical additional stress.

4. The method for grouting multiple bladder tubes to control uniform elevation of roadbed according to claim 3, characterized in that... In step S3, based on the dimensionless different depths The zero-point location mentioned above, when plotted using interpolation to obtain the dimensionless zero vertical additional stress envelope curve, refers to: when =0, hour, It is 0.425; when =0, hour, It is 0.422; when =0, hour, It is 0.404; when =0, hour, It is 0.367; when =0, hour, It is 0.309; when =0, hour, It is 0.228; when =0, hour, It is 0.

122.

5. The method for grouting multiple bladder tubes to control uniform elevation of roadbed according to claim 1, characterized in that... In step S4, the preset threshold is 0.84.

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