A polymer grouting reinforcement method to prevent airport road slab from lifting

Abstract

The present invention discloses a polymer grouting reinforcement method for preventing airport runway slab uplift, comprising the following steps: obtaining data on voids beneath the runway slab; constructing a polymer grouting reinforcement model; obtaining a qualified initial density of the polymer material based on the polymer grouting reinforcement model and the void data beneath the runway slab; and calculating the grouting rate based on the obtained qualified initial density of the polymer material, thereby completing the polymer grouting. The method of the present invention can effectively control the uplift of the runway slab while providing refined filling and reinforcement of the voids, significantly improving the rationality of the polymer grouting reinforcement scheme design and construction, ensuring the long-term stability and durability of the grouting reinforcement project, and providing strong support for the long-term stable operation and safety management of airport runways.

Description

Technical Field

[0001] This patent belongs to the field of foundation treatment calculation, and specifically relates to a polymer grouting reinforcement method for preventing airport road panel lifting. Background Art

[0002] The safe operation of airport runways is crucial to maintaining the normal functioning of my country's air transportation system. However, due to factors such as poor drainage, pavement cracking, and aircraft loads, many domestic airport runways face a range of problems. Among these, water-rich cavities, formed beneath the pavement slab by the suction effect of dynamic loads, are particularly prominent. These water-rich cavities significantly reduce the bearing capacity of the subgrade, negatively impacting the long-term performance of the runway.

[0003] In engineering practice, grouting is often used to fill and reinforce water-rich cavities in airport runway foundations. However, traditional Portland cement is not suitable for cavities containing large amounts of accumulated water. This often results in grouting reinforcement failing to meet expectations, and it's difficult to ensure the long-term stable operation of the reinforced runway.

[0004] To address this issue, a hydrophobic polymer grouting material has been used to fill and reinforce voids in airport roadbeds. However, the self-expansion properties of polymers can cause secondary expansion of voids or bulges in the road slab, negatively impacting the reinforcement. Currently, there is a lack of effective computational methods to accurately predict and control the effects of polymer self-expansion on subsurface voids and the overlying road slab. Summary of the Invention

[0005] The purpose of the present invention is to provide a polymer grouting reinforcement method for preventing the lifting of airport road panels, which can accurately predict and control the influence of the self-expansion force of the polymer on the cavity under the road surface and the overlying road panel.

[0006] The present invention provides a polymer grouting reinforcement method for preventing airport road slab from lifting, comprising the following steps:

[0007] S1. Obtain the cavity data under the airport road panel;

[0008] S2. Constructing polymer grouting reinforcement model;

[0009] S3. According to the polymer grouting reinforcement model obtained in step S2 and the cavity data under the airport road panel obtained in step S1, the initial density of the polymer material that meets the conditions is obtained;

[0010] S4. Calculate the grouting rate based on the initial density of the polymer material that meets the requirements obtained in step S3, and complete the polymer grouting.

[0011] The cavity data under the airport road panel in step S1 includes the cavity radius R0 and length L;

[0012] Specifically, step S2 is to construct a polymer grouting reinforcement model based on the pore expansion theory. The polymer grouting reinforcement model is a model that describes the equilibrium relationship between the decreasing self-expansion pressure of the polymer material and the increasing soil confining pressure. The model includes a soil confining pressure model and a polymer self-expansion pressure model. The soil confining pressure model is expressed using the following formula:

[0013]

[0014] Among them, R0 is the cavity radius; R u is the expansion radius; v is the Poisson's ratio of the soil; E is the elastic modulus of the soil; P p is the critical stress at which the soil enters the plastic state; P0 is the initial stress of the soil; α and Y are the parameters to be calculated; the ratio of the elastic-plastic interface radius to the expansion radius λ is calculated using the following formula:

[0015]

[0016] Among them, R p is the radius of the elastic-plastic interface; P is the pressure required for the cavity to expand;

[0017] The critical stress P at which the soil enters the plastic state p Use the following formula to calculate:

[0018]

[0019] According to elastic-plastic mechanics, the stress at any point in the surrounding soil should satisfy the equilibrium equation:

[0020]

[0021] Where r is the distance from the center of the cavity to the stress calculation point in the soil; σ r is the radial stress of the soil; σ θ is the circumferential stress of the soil;

[0022] The model also satisfies the boundary conditions, which can be expressed using the following formula:

[0023]

[0024] α and Y are calculated using the Mohr-Coulomb yield criterion and expressed using the following formula:

[0025]

[0026] Where c is the cohesion of the soil; is the internal friction angle of the soil;

[0027] The polymer self-expansion pressure model is expressed using the following formula:

[0028] p=1.1583ρ0δ 2

[0029] Where p is the self-expansion pressure; ρ0 is the initial density of the polymer material; δ is the expansion range.

[0030] Step S3 specifically comprises: presetting a polymer density as the current polymer initial density ρ0, using the ratio of the initial radius to the expansion radius δ0 to characterize the expansion range of the polymer material, substituting a plurality of preset δ0 values ​​into the polymer self-expansion pressure model in descending order to calculate a plurality of corresponding self-expansion pressures, and then sequentially substituting the obtained corresponding self-expansion pressures into the soil confining pressure model as the pressures P required for cavity expansion to obtain a plurality of corresponding expansion ranges δ'; comparing the preset expansion range δ0 with the corresponding expansion range δ' in the order of substitution calculation, and when δ'≤δ0 occurs for the first time, using the expansion range δ' at that time as the cavity expansion range δ;

[0031] Based on the obtained expansion range of the void, δ, the density change of the polymer material before and after expansion is determined using the following formula:

[0032] ρ=ρ0δ 2

[0033] Where ρ is the density of the expanded polymer material. Based on the known test results of polymer mechanical properties, the density of the expanded polymer material is used to obtain the ultimate strength and stiffness of the polymer material solidified at the corresponding density, and the grouting reinforcement effect is predicted. If the polymer grouting reinforcement effect meets the preset conditions, the next step is judged. Otherwise, the initial polymer density is reset and the above steps are repeated for trial calculation.

[0034] If the polymer grouting reinforcement effect reaches the preset conditions, the following formula is used to calculate the lifting force on the airport runway panel after the polymer material expands:

[0035] F=3.3166ρ0R0L

[0036] Wherein, F is the lifting force exerted on the airport runway panel by the expansion of the polymer material;

[0037] When F is greater than or equal to the weight of the pavement panel, the lifting force generated by the expansion of the polymer is greater than the weight of the pavement panel, and the pavement structure will bulge uncontrollably; when F is less than the weight of the pavement panel, the pavement structure will not move upward.

[0038] If the road panel is not lifted, the initial density is the initial density of the polymer grouting material that meets the conditions ρ lOtherwise, reset the initial density of the polymer and perform trial calculations according to the above steps until the initial density of the polymer material that meets the requirements is obtained; meeting the requirements means that the polymer grouting reinforcement effect reaches the preset conditions and the lifting force of the polymer material on the airport road panel after expansion is less than the weight of the road panel.

[0039] Step S4 specifically includes: setting the polymer foaming reaction time to ts, and performing grouting to fill the cavity under the airport road panel before the reaction time ends;

[0040] The initial density ρ of the polymer that meets the conditions obtained in step S3 l , calculate the mass of polymer material that needs to be injected, using the following formula:

[0041]

[0042] Then calculate the minimum grouting rate Q using the following formula:

[0043]

[0044] Finally, the polymer grouting reinforcement is completed according to the obtained parameters.

[0045] The present invention discloses a polymer grouting reinforcement method for preventing the lifting of airport runway panels. The method can effectively control the lifting of the runway panels while performing refined filling and reinforcement of the voids, significantly improving the rationality of the design and construction of the polymer grouting reinforcement scheme, ensuring the long-term stability and durability of the grouting reinforcement project, and providing strong support for the long-term stable operation and safety management of airport runways. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of the process of the present invention;

[0047] Figure 2 Graph showing the relationship between density and ultimate strength of polymer materials in an embodiment of the present invention;

[0048] Figure 3 Graph showing the relationship between density and elastic modulus of polymer materials in an embodiment of the present invention;

[0049] Figure 4 Schematic diagram of the airport runway cavity in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The present invention provides a polymer grouting reinforcement method for preventing the lifting of airport road panels, the flow diagram of which is as follows: Figure 1 As shown, the following steps are included:

[0051] S1. Obtain the cavity data under the airport road panel;

[0052] The cavity data under the airport road panel includes cavity radius R0 and length L;

[0053] S2. Construct a polymer grouting reinforcement model, specifically:

[0054] Based on the pore expansion theory, a polymer grouting reinforcement model is constructed. The polymer grouting reinforcement model describes the equilibrium relationship between the decreasing self-expansion pressure of the polymer material and the increasing soil confining pressure. It includes a soil confining pressure model and a polymer self-expansion pressure model. The soil confining pressure model is expressed using the following formula:

[0055]

[0056] Among them, R0 is the cavity radius; R u is the expansion radius; v is the Poisson's ratio of the soil; E is the elastic modulus of the soil; P p is the critical stress at which the soil enters the plastic state; P0 is the initial stress of the soil; α and Y are the parameters to be calculated; the ratio of the elastic-plastic interface radius to the expansion radius λ is calculated using the following formula:

[0057]

[0058] Among them, R p is the radius of the elastic-plastic interface; P is the pressure required for the cavity to expand;

[0059] The critical stress P at which the soil enters the plastic state p Use the following formula to calculate:

[0060]

[0061] According to elastic-plastic mechanics, the stress at any point in the surrounding soil should satisfy the equilibrium equation:

[0062]

[0063] Where r is the distance from the center of the cavity to the stress calculation point in the soil; σ r is the radial stress of the soil; σ θ is the circumferential stress of the soil;

[0064] The model also satisfies the boundary conditions, which can be expressed using the following formula:

[0065]

[0066] α and Y are calculated using the Mohr-Coulomb yield criterion and expressed using the following formula:

[0067]

[0068] Where c is the cohesion of the soil; is the internal friction angle of the soil;

[0069] The polymer self-expansion pressure model is expressed using the following formula:

[0070] p=1.1583ρ0δ 2

[0071] Where p is the self-expansion pressure; ρ0 is the initial density of the polymer material; δ is the expansion range.

[0072] S3. Based on the polymer grouting reinforcement model obtained in step S2 and the cavity data under the airport road panel obtained in step S1, the initial density of the polymer material that meets the conditions is obtained, specifically:

[0073] A polymer density is preset as the current polymer initial density ρ0, and the ratio of the initial radius to the expansion radius δ0 is used to characterize the expansion range of the polymer material. Several preset δ0 values ​​are substituted into the polymer self-expansion pressure model in descending order to calculate several corresponding self-expansion pressures. The corresponding self-expansion pressures obtained are then sequentially substituted into the soil confining pressure model as the pressures P required for cavity expansion to obtain several corresponding expansion ranges δ'; the preset expansion range δ0 is compared with the corresponding expansion range δ' in the order of substitution calculation. When δ'≤δ0 appears for the first time, the expansion range δ' at this time is used as the cavity expansion range δ;

[0074] Based on the obtained expansion range of the void, δ, the density change of the polymer material before and after expansion is determined using the following formula:

[0075] ρ=ρ0δ 2

[0076] Where ρ is the density of the expanded polymer material. Based on the known test results of polymer mechanical properties, the density of the expanded polymer material is used to obtain the ultimate strength and stiffness of the polymer material solidified at the corresponding density, and the grouting reinforcement effect is predicted. If the polymer grouting reinforcement effect meets the preset conditions, the next step is judged. Otherwise, the initial polymer density is reset and the above steps are repeated for trial calculation.

[0077] If the polymer grouting reinforcement effect reaches the preset conditions, the following formula is used to calculate the lifting force on the airport runway panel after the polymer material expands:

[0078] F=3.3166ρ0R0L

[0079] Wherein, F is the lifting force exerted on the airport runway panel by the expansion of the polymer material;

[0080] When F is greater than or equal to the weight of the pavement panel, the lifting force generated by the expansion of the polymer is greater than the weight of the pavement panel, and the pavement structure will bulge uncontrollably; when F is less than the weight of the pavement panel, the pavement structure will not move upward.

[0081] If the road panel is not lifted, the initial density is the initial density of the polymer grouting material that meets the conditions ρ l Otherwise, reset the initial density of the polymer and perform trial calculations according to the above steps until the initial density of the polymer material that meets the requirements is obtained; meeting the requirements means that the polymer grouting reinforcement effect reaches the preset conditions and the lifting force of the polymer material on the airport road panel after expansion is less than the weight of the road panel.

[0082] S4. Based on the initial density of the polymer material that meets the conditions obtained in step S3, the grouting rate is calculated and the polymer grouting is completed, specifically:

[0083] Set the polymer foaming reaction time to ts, and fill the cavity under the airport road panel with grouting before the reaction time ends;

[0084] The initial density ρ of the polymer that meets the conditions obtained in step S3 l , calculate the mass of polymer material that needs to be injected, using the following formula:

[0085]

[0086] Then calculate the minimum grouting rate Q using the following formula:

[0087]

[0088] Finally, the polymer grouting reinforcement is completed according to the obtained parameters.

[0089] The method of the present invention is further described below with reference to an embodiment:

[0090] A cavity is generated under an airport runway. The runway structure consists of a concrete pavement, a roadbed, a cushion layer, and a soil base. The soil friction angle is 20°, the cohesion is 6 kPa, the Poisson's ratio is 0.3, and the elastic modulus is 25 MPa. There is a semi-cylinder with a radius (R0) of 10 cm and a length (L) of 40 cm in the soil base. Figure 4 shown.

[0091] First, the initial density of the polymer material in the reinforcement scheme is preset to 0.32 g / cm 2 The reinforcement effect of the reinforcement scheme was analyzed using the method of the present invention. The results showed that the cavity expansion radius under the self-expansion of the polymer was 10.57 cm, and the density of the polymer solidified body after cavity expansion was 0.286 g / cm 3 .

[0092] according to Figure 1 and Figure 2 The relationship between polymer density, ultimate strength, and elastic modulus was plotted in the figure to determine the self-expansion radius of the polymer foam and the strength of the polymer after expansion. The ultimate strength of the polymer material was determined to be 3.6 MPa, and the elastic modulus was 60 MPa. Based on the known conditions of the airport road, a compressive strength of 3.4 MPa and an elastic modulus of 50 MPa are sufficient to effectively control pavement settlement. Therefore, the mechanical properties of the reinforced roadbed with this solution ensure the long-term performance of the pavement.

[0093] Furthermore, calculations show that the maximum self-expansion force of the polymer in this reinforcement scheme is 0.37 MPa, and the lifting force is 42.45 kN, while the weight of the road slab is approximately 392 kN. Therefore, the road surface structure will not be lifted, and the stability of the overlying structure can be controlled while strengthening the roadbed.

[0094] Finally, the polymer foaming reaction time was set to 20s, and the grouting parameters were calculated. The mass of the grouting polymer material was obtained to be 2000g, and the minimum grouting rate was 100g / s. According to the above grouting parameters, the construction design was carried out to complete the refined grouting reinforcement of the airport roadbed cavity.

Claims

1. A polymer grouting reinforcement method for preventing airport road panel lifting, characterized in that: The following steps are involved: S1. Obtain the cavity data under the airport road panel; S2. Constructing polymer grouting reinforcement model; S3. According to the polymer grouting reinforcement model obtained in step S2 and the cavity data under the airport road panel obtained in step S1, the initial density of the polymer material that meets the conditions is obtained; S4 according to the initial density of the polymer material that meets the conditions obtained in step S3, the grouting rate is calculated to complete the polymer grouting; The cavity data under the airport road panel in step S1 includes the cavity radius and length ; Step S2 specifically includes: constructing a polymer grouting reinforcement model based on the pore expansion theory; the polymer grouting reinforcement model is a model that describes the equilibrium relationship between the decreasing self-expansion pressure of the polymer material and the increasing soil confining pressure, including a soil confining pressure model and a polymer self-expansion pressure model. The soil confining pressure model is expressed using the following formula: ,in, is the cavity radius; is the expansion radius; is the Poisson's ratio of the soil; is the elastic modulus of soil; is the critical stress at which the soil enters the plastic state; is the initial stress of the soil; and is the parameter to be calculated; the ratio of the elastic-plastic interface radius to the expansion radius Use the following formula to calculate: ,in, is the radius of the elastic-plastic interface; The pressure required for cavity expansion; Critical stress for soil to enter plastic state Use the following formula to calculate: According to elastic-plastic mechanics, the stress at any point in the surrounding soil should satisfy the equilibrium equation: ,in, is the distance from the center of the cavity to the stress calculation point in the soil; is the radial stress of the soil; is the circumferential stress of the soil; The model also satisfies the boundary conditions, which can be expressed using the following formula: 、 , calculated using the Mohr-Coulomb yield criterion, and expressed using the following formula: ,in, is the cohesion of the soil; is the internal friction angle of the soil; The polymer self-expansion pressure model is expressed using the following formula: ,in, is the self-expansion pressure; is the initial density of the polymer material; To expand the scope; Step S3 specifically includes: presetting a polymer density as the current polymer initial density , using the ratio of the initial radius to the expansion radius To characterize the expansion range of polymer materials, several preset The values ​​are substituted into the polymer self-expansion pressure model in descending order to calculate the corresponding self-expansion pressures, and then the corresponding self-expansion pressures are used as the pressure required for cavity expansion. Substitute them into the soil confining pressure model in sequence to obtain the corresponding expansion ranges ; Set the preset expansion range in the order of substitution calculation Corresponding expansion range Compare, when first appeared When the expansion range is As the expansion range of the void ; According to the expansion range of the obtained cavity , determine the density change of polymer material before and after expansion, and use the following formula to calculate: ,in, is the density of the expanded polymer material; based on the known test results of polymer mechanical properties, the density of the expanded polymer material is used to obtain the ultimate strength and stiffness of the polymer material solidified body at the corresponding density, and the grouting reinforcement effect is predicted. If the polymer grouting reinforcement effect meets the preset conditions, the next step is judged; otherwise, the initial polymer density is reset and the above steps are repeated for trial calculation; If the polymer grouting reinforcement effect reaches the preset conditions, the following formula is used to calculate the lifting force on the airport runway panel after the polymer material expands: ,in, It is the lifting force on the airport runway panel after the expansion of the polymer material; when When the weight of the road surface is greater than or equal to the weight of the road surface, the lifting force generated by the expansion of the polymer is greater than the weight of the road surface, and the road surface structure will bulge uncontrollably; when When the force is less than the weight of the road surface, the road surface structure will not move upward; If the road panel is not lifted, the initial density is the initial density of the polymer grouting that meets the conditions. Otherwise, reset the initial density of the polymer and perform trial calculations according to the above steps until the initial density of the polymer material that meets the requirements is obtained; meeting the requirements means that the polymer grouting reinforcement effect reaches the preset conditions and the lifting force of the polymer material on the airport road panel after expansion is less than the weight of the road panel.

2. The polymer grouting reinforcement method for preventing the lifting of airport road panels according to claim 1 is characterized in that: Step S4 is specifically as follows: setting the polymer foaming reaction time to s, it is necessary to fill the voids under the airport road slab with grouting before the end of the reaction time; The initial density of the polymer material grouting that meets the conditions obtained in step S3 , calculate the mass of polymer material that needs to be injected, using the following formula: , and then calculate the grouting rate , use the following formula to calculate: Finally, the polymer grouting reinforcement is completed according to the obtained parameters.

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