High polymer grouting reinforcement method for preventing airport pavement slab from being lifted

Abstract

The invention discloses a high polymer grouting reinforcement method for preventing an airport pavement slab from being lifted. The high polymer grouting reinforcement method comprises the following steps: acquiring cavity data under the airport pavement slab; constructing a high polymer grouting reinforcement model; according to the high polymer grouting reinforcement model and the cavity data under the airport pavement slab, the initial density of a high polymer material meeting the conditions is obtained; and according to the obtained initial density of the high polymer material meeting the conditions, the grouting rate is obtained through calculation, and high polymer grouting is completed. According to the method, the cavities can be finely filled and reinforced while the pavement slab can be effectively controlled to be lifted, the reasonability of high polymer grouting reinforcement scheme design and construction is remarkably improved, the long-term stability and durability of grouting reinforcement engineering are guaranteed, and powerful support is provided for 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 slab from lifting. Background Art

[0002] The safe operation of airport runways is of vital importance to maintaining the normal operation of my country's aviation transportation system. However, due to many factors such as poor drainage, pavement cracking and aircraft loads, many domestic airport runways are facing a series of disease problems, among which the phenomenon of water-rich cavities formed under the pavement slab by the suction effect of dynamic loads is particularly prominent. Such water-rich cavities will significantly reduce the bearing capacity of the pavement foundation, thereby adversely affecting the long-term service performance of the runway.

[0003] In engineering practice, grouting is often used to fill and reinforce water-rich holes in airport runways. However, the applicability of traditional silicate cement materials is insufficient for holes with a large amount of accumulated water. As a result, the actual grouting reinforcement effect is often difficult to achieve as expected, and it is impossible to ensure that the reinforced airport runway can operate stably for a long time.

[0004] To solve this problem, a water-repellent polymer grouting material was applied to fill and reinforce the voids in the airport roadbed. However, the self-expansion characteristics of the polymer material may cause secondary expansion of the voids or bulge of the road slab, which has an adverse effect on the reinforcement effect. At present, there is still a lack of an effective calculation method to accurately predict and control the effect of the polymer self-expansion force on the voids under the road surface 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 airport road surface from lifting, 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 surface.

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

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

[0008] S2. Construct polymer grouting reinforcement model;

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

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

[0011] Step S1: The cavity data under the airport runway panel includes the cavity radius R0 and length L;

[0012] 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:

[0013]

[0014] Where 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 for the soil to enter 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 of the soil entering the plastic state p Use the following calculation:

[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 void 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 are expressed as follows:

[0023]

[0024] α and Y are calculated by 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 is specifically as follows: a polymer density is preset as the current polymer initial density ρ0, a ratio of the initial radius to the expansion radius δ0 is used to characterize the expansion range of the polymer material, a plurality of preset δ0 values ​​are substituted in descending order into the polymer self-expansion pressure model to calculate a plurality of corresponding self-expansion pressures, and then the corresponding plurality of self-expansion pressures are sequentially substituted into the soil confining pressure model as the pressure P required for cavity expansion to obtain a plurality of corresponding expansion ranges δ'; the preset expansion range δ0 is compared with the corresponding expansion range δ' in the order of substitution calculation, and when δ'≤δ0 appears for the first time, the expansion range δ' at this time is used as the expansion range δ of the cavity;

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

[0032] ρ=ρ0δ 2

[0033] Wherein, ρ is the density of the expanded polymer material; according to 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 solid 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 to be judged, otherwise the initial density of the polymer is reset and the trial calculation is performed according to the above steps;

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

[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 gravity of the pavement panel, the lifting force generated by the expansion of the polymer is greater than the gravity of the pavement panel, and the pavement structure will bulge uncontrollably; when F is less than the gravity of the pavement panel, the pavement structure will not move upward;

[0038] If the road slab is not lifted, the initial density is the initial density of the polymer material grouting 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 pavement panel after expansion is less than the weight of the pavement panel.

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

[0040] The initial density 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, which 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 It is a schematic diagram of the process of the present invention;

[0047] Figure 2 is a graph showing the relationship between the density and ultimate strength of a polymer material in an embodiment of the present invention;

[0048] Figure 3 is a graph showing the relationship between the density and elastic modulus of a polymer material 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, and its process diagram 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 runway 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 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 the soil confining pressure model and the polymer self-expansion pressure model. The soil confining pressure model is expressed by the following formula:

[0055]

[0056] Where 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 for the soil to enter 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 of the soil entering the plastic state p Use the following calculation:

[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 void 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 are expressed as follows:

[0065]

[0066] α and Y are calculated by 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. 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, 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. A plurality of preset δ0 values ​​are substituted into the polymer self-expansion pressure model in descending order to calculate a plurality of corresponding self-expansion pressures, and then the corresponding plurality of self-expansion pressures are sequentially substituted into the soil confining pressure model as the pressure P required for cavity expansion to obtain a plurality of corresponding expansion ranges δ'; the preset expansion range δ0 is compared with the corresponding expansion range δ' in the order of substitution calculation, and when δ'≤δ0 appears for the first time, the expansion range δ' at this time is used as the expansion range δ of the cavity;

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

[0075] ρ=ρ0δ 2

[0076] Wherein, ρ is the density of the expanded polymer material; according to 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 solid 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 to be judged, otherwise the initial density of the polymer is reset and the trial calculation is performed according to the above steps;

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

[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 gravity of the pavement panel, the lifting force generated by the expansion of the polymer is greater than the gravity of the pavement panel, and the pavement structure will bulge uncontrollably; when F is less than the gravity of the pavement panel, the pavement structure will not move upward;

[0081] If the road slab is not lifted, the initial density is the initial density of the polymer material grouting 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 pavement panel after expansion is less than the weight of the pavement panel.

[0082] 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, specifically:

[0083] The polymer foaming reaction time is set to ts, and the cavity under the airport road panel needs to be filled with grout before the reaction time ends;

[0084] The initial density 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 in conjunction with an embodiment:

[0090] A cavity is generated under an airport runway. The runway structure consists of concrete pavement, roadbed, cushion layer, and 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, and the cavity expansion radius under the self-expansion of the polymer was found to be 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 the polymer material density and the ultimate strength and elastic modulus in the figure is used to determine the self-expansion radius of the polymer foam and the strength performance of the polymer after expansion. The ultimate strength of the polymer material is 3.6MPa and the elastic modulus is 60MPa. According to the known conditions of the airport road, the compressive strength of 3.4MPa and the elastic modulus of 50MPa are sufficient to effectively control the pavement settlement. Therefore, the mechanical properties of the roadbed after reinforcement by this scheme can guarantee the long-term performance of the pavement.

[0093] In addition, the maximum self-expansion force of the polymer in this reinforcement scheme is calculated to be 0.37MPa, the lifting force is 42.45KN, and the weight of the road surface is about 392KN. Therefore, the road surface structure will not be lifted up, 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. The construction design was carried out according to the above grouting parameters to complete the refined grouting reinforcement of the airport roadbed voids.

Claims

1. A polymer grouting reinforcement method for preventing airport road panel from lifting, characterized in that: The following steps are involved: S1. Obtain the cavity data under the airport road panel; S2. Construct polymer grouting reinforcement model; S3. Obtaining the initial density of the polymer material that meets the conditions according to the polymer grouting reinforcement model obtained in step S2 and the cavity data under the airport road panel obtained in step S1; S4. Calculate the grouting rate based on the initial density of the polymer material that meets the conditions obtained in step S3, and complete the polymer grouting.

2. The polymer grouting reinforcement method for preventing the airport road slab from lifting according to claim 1 is characterized in that: The cavity data under the airport runway panel in step S1 includes the cavity radius R0 and length L.

3. The polymer grouting reinforcement method for preventing the airport road slab from lifting according to claim 2 is characterized in that: 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 by the following formula: Where 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 for the soil to enter 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: Among them, R p is the radius of the elastic-plastic interface; P is the pressure required for the cavity to expand; The critical stress P of the soil entering the plastic state p Use the following calculation: According to elastic-plastic mechanics, the stress at any point in the surrounding soil should satisfy the equilibrium equation: Where r is the distance from the center of the void 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; The model also satisfies the boundary conditions, which can be expressed using the following formula: α and Y are calculated by the Mohr-Coulomb yield criterion and expressed using the following formula: Where c 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: p=1.1583ρ0δ 2 Where p is the self-expansion pressure; ρ0 is the initial density of the polymer material; δ is the expansion range.

4. The polymer grouting reinforcement method for preventing airport road slab from lifting according to claim 3 is characterized in that: Step S3 specifically includes: 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, presetting a number of δ0 values ​​and substituting them into the polymer self-expansion pressure model in descending order to calculate a number of corresponding self-expansion pressures, and then sequentially substituting the obtained corresponding self-expansion pressures into the soil confining pressure model as the pressure P required for cavity expansion to obtain a number of corresponding expansion ranges δ'; Compare the preset expansion range δ0 with the corresponding expansion range δ' in the order of substitution calculation. When δ'≤δ0 appears for the first time, take the expansion range δ' at this time as the expansion range δ of the cavity; According to the obtained expansion range of the void δ, the density change of the polymer material before and after expansion is determined and calculated using the following formula: p=ρ0δ 2 Wherein, ρ is the density of the expanded polymer material; according to 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 solid 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 to be judged, otherwise the initial density of the polymer is reset and the trial calculation is performed according to the above steps; If the polymer grouting reinforcement effect reaches the preset conditions, the following formula is used to calculate the lifting force of the polymer material on the airport runway panel after expansion: F=3.3166ρ0R0L Wherein, F is the lifting force exerted on the airport runway panel by the expansion of the polymer material; When F is greater than or equal to the gravity of the pavement panel, the lifting force generated by the expansion of the polymer is greater than the gravity of the pavement panel, and the pavement structure will bulge uncontrollably; when F is less than the gravity of the pavement panel, the pavement structure will not move upward; If the road slab is not lifted, the initial density is the initial density of the polymer material grouting 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 pavement panel after expansion is less than the weight of the pavement panel.

5. The polymer grouting reinforcement method for preventing the airport road slab from lifting according to claim 4 is characterized in that: Step S4 specifically includes: setting the polymer foaming reaction time to ts, and performing grouting filling on the cavity under the airport road panel before the reaction time ends; The initial density 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: Then calculate the grouting rate Q using the following formula: Finally, the polymer grouting reinforcement is completed according to the obtained parameters.

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