ABAQUS-based method for judging vehicle passing performance of flexible quick-hardening cement blanket pavement

Abstract

The invention relates to an ABAQUS-based method for judging the vehicle passing performance of a flexible quick-hardening cement blanket pavement. The ABAQUS is used for constructing a finite element model of the flexible quick-hardening cement blanket pavement and a natural foundation; by means of a VDload subprogram in ABAQUS software, vehicle loads are coded and accessed into a finite element model for calculation, and the relation between the road surface subsidence amount and the vehicle loads, the vehicle speed and the road surface thickness is established; and determining the vehicle passing performance of the flexible quick-hardening cement blanket pavement based on the to-be-predicted soil body by means of analysis of an emergency pavement passing performance judgment theory. Aiming at the specific object of the temporary pavement structure, establishing a relation between the characteristic parameters capable of expressing the vehicle load-subsidence quantity relation and the pavement thickness and the vehicle speed, and predicting the passing performance of the temporary pavement structure when the temporary pavement structure bears different vehicle loads on the foundation to be predicted; and the efficiency and the safety when the temporary road surface is used for emergency traffic guarantee are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of cement blanket pavement performance testing technology, and in particular to a method for determining the vehicle passing performance of flexible rapid-hardening cement blanket pavement based on ABAQUS and a flexible rapid-hardening cement blanket pavement structure. Background Technology

[0002] Cement blankets, also known as concrete canvas, are an innovative building material that combines the properties of cement and textiles. They offer advantages such as rollability for transport and the ability to be used immediately after water is sprayed on the surface and allowed to harden. They are suitable for various applications including ditch lining, slope protection, and pipeline protection. Recent research shows that concrete cement blankets have comparable hardness and service life to traditional cement, but they simplify the construction process, reduce cumbersome steps, save manpower, and lower production costs, making them suitable for a wide range of applications. Depending on the processing method, cement blankets can be divided into needle-punched and three-dimensional woven types. Three-dimensional spaced-fiber cement blankets, due to their three-dimensional fiber reinforcement, possess higher material strength and durability. The three-dimensional fiber structure also provides good drape and adaptability to complex shapes, exhibiting good flexibility and toughness. However, currently, most traditional cement blankets on the market use silicate cement and sulfoaluminate cement as the matrix material, which suffers from slow hardening speed and strength reduction, thus failing to adequately meet the needs of emergency scenarios.

[0003] my country has a vast territory with large areas of deserts and tidal flats, frequently resulting in vehicles and people becoming trapped. Furthermore, during natural disasters such as earthquakes and floods, many sections of roads leading to disaster areas have low load-bearing capacity. Traditional methods for improving road surface load-bearing capacity are time-consuming and labor-intensive. Therefore, to ensure rapid rescue operations in these emergencies, it is necessary to quickly construct an emergency road surface that solves traffic problems. Considering the advantages of cement blankets, such as flexibility, economy, and ease of construction, it is of great significance to explore their potential as a temporary road structure and study their vehicle passability.

[0004] Currently, the evaluation of vehicle passability mainly relies on theoretical calculations and empirical judgments. Theoretical calculation methods are usually based on the deformation mode of the road surface and the interaction between the tire, road surface, and soil, and assume the ground load of the wheels. q Maximum road surface subsidence caused by vehicles passing by h 0 linear dependence (i.e.) q = kh 0) This establishes a relationship between vehicle load and settlement. Based on the above theoretical analysis, it compares the driving force of the road surface on the tires and the rolling resistance generated by the tires overcoming ground deformation to determine whether a vehicle can pass. However, this theoretical calculation method ignores the influence of vehicle speed and road thickness, relying solely on a single control parameter.k There is no way to accurately reflect the relationship between vehicle load and pavement settlement under the influence of multiple factors. On the other hand, although the results of physical tests are intuitive and reliable, they are usually time-consuming, labor-intensive, costly, and difficult to cover all possible working conditions, especially in large-scale engineering applications or design optimization stages, the efficiency, flexibility and safety of physical tests are difficult to guarantee. SUMMARY

[0005] The first object of the present application is to provide a method for determining the vehicle passing performance of flexible rapid hardening cement carpet pavement based on ABAQUS, to solve the problem of incomplete consideration in theoretical calculation and huge resource consumption in physical test in the prior art.

[0006] The second object of the present application is to provide a flexible rapid hardening cement carpet pavement structure, which has the characteristics of fast hardening and early strength, and can meet the demand of emergency traffic.

[0007] In order to achieve the above-mentioned first object, the technical scheme adopted by the present application is as follows: A method for determining the vehicle passing performance of flexible rapid hardening cement carpet pavement based on ABAQUS, applied to flexible rapid hardening cement carpet, the method comprises the following contents: Constructing a finite element model of flexible rapid hardening cement carpet pavement and natural foundation by using ABAQUS software; Based on the finite element model, selecting the maximum value of the stress of each wheel of the vehicle on the ground as the vehicle load q Obtaining the maximum pavement settlement caused by different vehicle loads in the driving process under different pavement thicknesses and vehicle speeds h 0 According to q = kh 0 n Fitting the relationship between vehicle load q and pavement settlement h 0 under different pavement thicknesses and vehicle speeds, to obtain the control parameters k , n under different working conditions; According to the data group composed of k and vehicle speed v , pavement thickness t fitting to obtain the expression of control parameter k about vehicle speed v and pavement thickness t f k ( v , t );Meanwhile, according to n and vehicle speed v , pavement thickness t ​fitting the data set composed of the data n about the vehicle speed v and the thickness of the pavement t expression f n v t The passability judgment formula of the flexible rapid-hardening cement pavement is:

[0008] When Pi is greater than 0, it is considered that the vehicle can pass; when Pi is less than or equal to 0, it is considered that the vehicle cannot pass; wherein Pi is the passability criterion; μ is the adhesion coefficient between the tire and the pavement; q is the vehicle load, R represents the tire radius.

[0009] Further, the finite element model of the flexible rapid-hardening cement pavement and the natural foundation is constructed by using ABAQUS, comprising: A1. The flexible rapid-hardening cement pavement model is simplified into three parts of concrete, dense fabric and sparse fabric; A2. The plastic damage model of concrete provided by ABAQUS is used as the concrete material model, and the corresponding material property test is carried out according to the model requirements to obtain the related parameters; A3. The fabric is regarded as an orthotropic plate model, and the constitutive relation of the fabric is established; A4. The Mohr-Coulomb model in ABAQUS is used to simulate the stress-strain relationship of the predicted natural foundation soil.

[0010] Further, the finite element model is adjusted and the accuracy of the model is verified by using the field test results, comprising: B1. The pavement is laid on the measured foundation in accordance with the actual scale of the field test by using ABAQUS software; B2. The vehicle load in accordance with the actual situation is programmed by using the VDload subprogram in ABAQUS software, and the vehicle load is connected to the finite element model for calculation; B3. The pavement settlement amount of the vehicle passing back and forth 10 times in the field is compared with the numerical simulation result, so as to adjust the model and verify the accuracy of the finite element model, so that the numerical simulation result is infinitely close to the measured data.

[0011] Further, the model is adjusted, comprising the following steps: C1. The parameter value range of the measured foundation soil required to be input into ABAQUS software is determined through literature research; ​​​C2. Adjust the model according to the rut depth development curve of the field test results, and adjust and invert the parameters of the foundation model based on the parameter value range of the above-mentioned to-be-tested foundation soil, until a satisfactory simulation accuracy is obtained; C3. If the simulation result is not accurate, locally refine the mesh in the area directly affected by the wheel load; C4. For the interface between the pavement layer and the foundation layer, a binding contact is usually used, and to improve the accuracy of the model, interlayer slip can be considered and a friction contact can be set. Further, the flexible rapid hardening cement carpet includes a three-dimensional spacing fabric, a geopolymer matrix, and a packaging material, and the adhesion coefficient between the tire and the road surface on the soft foundation is 0.05-0.2. μ When analyzing the interaction among the tire, the road surface and the soil, the horizontal tension of the cement carpet pavement is assumed to be 0.

[0012] Further, the thickness of the cement carpet pavement required to be laid based on the actual traffic condition on site can be deduced according to the determination formula; or the user can adjust and change the foundation and the temporary pavement structure according to the own demand, and calculate the vehicle traffic capacity of the target working condition according to the above-mentioned determination method.

[0013] Further, the method is suitable for the vehicle passability determination of the temporary pavement structure laid on various soft foundations, including sandy soil, silt and the like.

[0014] The application also protects a flexible rapid hardening cement carpet pavement structure, which is determined whether to meet the passability requirement by using the determination method, and includes a three-dimensional spacing fabric, a geopolymer matrix and a packaging material; wherein the geopolymer matrix includes fly ash, silica ash, blast furnace slag, magnesium oxide (MgO), calcium oxide (CaO) and alkali activator; and the three-dimensional spacing fabric includes a dense woven surface, a spacing yarn and a sparse woven surface.

[0015] Further, under the natural curing condition, the setting time is about 30 minutes, the 3h compressive strength is greater than or equal to 20MPa, and the 3h flexural strength is greater than or equal to 7MPa; the excellent adaptability and rapid response capability under the emergency conditions such as natural disasters such as earthquakes, heavy rains, landslides and the like, the cement carpet can be used for rapid transportation of materials, and can be rapidly laid on roads in complex geographical environments such as mountainous areas, desert areas, tidal areas and the like.

[0016] Compared with the prior art, the application has the following beneficial effects: (1) The flexible rapid hardening cement carpet pavement vehicle passability determination method based on ABAQUS can overcome the limitations of the existing theoretical and test methods. q =kh 0 n ), by setting multiple groups of working conditions, the relationship between vehicle load and pavement settlement is fitted, and the control parameters k 、 n and the relationship between the speed, the thickness of the pavement are fitted, combined with the interaction analysis of tire-pavement-soil, an emergency pavement passing performance discriminant formula considering multiple factors is obtained. According to the discriminant formula, the passing capacity of the flexible rapid hardening cement carpet pavement structure on the measured foundation for different vehicles can be efficiently and accurately inferred, and the thickness of the cement carpet pavement required based on the actual traffic situation can be inversely deduced, which has important significance for solving the traffic problem in emergency.

[0017] (2) The cement carpet pavement structure with geopolymer material as the matrix adopts geopolymer matrix and three-dimensional spacer fabric, has the characteristics of short setting time and high early strength, has the core advantage of "flexible early strength": under natural curing, the setting time is about 30min, which is much lower than the setting time of 48h of ordinary cement carpet. The prepared geopolymer cement carpet can reach the compressive strength comparable to that of traditional concrete at 7d, and can exceed the flexural strength of traditional cement carpet at 1d, specifically: 3h compressive strength≥20MPa, 3h flexural strength≥7MPa. The construction interval time of the cement carpet is greatly shortened, and the construction efficiency is improved. At the same time, it has good impermeability, fire resistance, acid and alkali corrosion resistance, can adapt to various complex extreme environments and emergency pavement repair engineering, and has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A flowchart of a flexible rapid hardening cement carpet pavement vehicle passing performance determination method based on ABAQUS is provided for the present application. Figure 2 A simplified finite element model structure diagram of the flexible rapid hardening cement carpet provided by the present application is provided. Figure 3 A grid diagram of the flexible rapid hardening cement carpet pavement provided by the present application is provided. Figure 4 A grid diagram of the measured natural foundation provided by the present application is provided. Figure 5 A schematic diagram of the overall model of the finite element model provided by the present application is provided. Figure 6 A numerical simulation result diagram based on field test provided by the present application is provided. Figure 7 A flexible rapid hardening cement carpet pavement rut center point deformation time history curve when the vehicle load is input for calculation is provided. Figure 8A comparison chart of a to-be-tested ground vehicle load-pavement settlement amount relationship curve and a fitting curve provided by the present application is shown in FIG. 1. Figure 9 A schematic diagram of interaction among a tire, a pavement and a soil body provided by the present application is shown in FIG. 2. Figure 10 A schematic diagram of a flexible rapid-hardening cement blanket sample provided by the present application is shown in FIG. 3. Figure 11 A schematic diagram of a flexible rapid-hardening cement blanket structure provided by the present application is shown in FIG. 4. DETAILED DESCRIPTION

[0019] The present application will be further described in conjunction with specific embodiments and the accompanying drawings. However, it should not be construed that the present application is limited to the scope of the present application, and any technology realized based on the content of the present application belongs to the scope of the present application.

[0020] Embodiment 1 The present embodiment provides a flexible rapid-hardening cement blanket pavement vehicle passing performance determination method based on ABAQUS, applied to a flexible rapid-hardening cement blanket including a three-dimensional spacer fabric, a geopolymer matrix and an encapsulating material. The method includes the following steps: A field test is carried out, the flexible rapid-hardening cement blanket pavement structure is laid on the soft soil foundation to be predicted, and a typical vehicle is selected for traffic test to illustrate the feasibility of the flexible rapid-hardening cement blanket as a temporary pavement; According to the cement blanket macrostructure and the material property test of concrete and fabric, and the investigation of the characteristic parameters of the to-be-predicted ground soil body, a finite element model of the flexible rapid-hardening cement blanket pavement and the natural ground is constructed by using ABAQUS, the model is adjusted by using the field test results, and the accuracy of the model is verified; The VDload subprogram in the ABAQUS software is borrowed to code the vehicle load and input into the finite element model for calculation, and the relationship among the pavement settlement amount, the vehicle load, the vehicle speed and the pavement thickness is established; The vehicle passing performance discrimination formula of the flexible rapid-hardening cement blanket pavement is determined by borrowing the emergency pavement passing performance determination theory analysis, and then the vehicle passing performance of the flexible rapid-hardening cement blanket pavement based on the to-be-predicted soil body is determined according to the discrimination formula.

[0021] Embodiment 2 The present embodiment provides a flexible rapid-hardening cement blanket pavement vehicle passing performance determination method based on ABAQUS, as shown in FIG. 5, the cement blanket sample in the present embodiment, as shown in FIG. 6, includes a three-dimensional spacer fabric 1, a geopolymer matrix 2 and an encapsulating material 3. Figure 1 Figure 10 Specifically, as shown in FIG. 7, the three-dimensional spacer fabric 1 is composed of a plurality of spacer fabrics 1a arranged in a three-dimensional manner.

[0022] Specifically, as shown in FIG. 7, the three-dimensional spacer fabric 1 is composed of a plurality of spacer fabrics 1a arranged in a three-dimensional manner. Figure 11 ​As shown in the figure, the three-dimensional spacer fabric includes a dense fabric surface 11, spacer yarn 12 and sparse fabric surface 13, the spacer yarn 12 is composed of warp and weft, the two ends of the spacer yarn 12 are connected to the dense fabric surface 11 and the sparse fabric surface 13 respectively, the thickness of the three-dimensional spacer fabric is 10mm, the sparse fabric surface 13 is uniformly provided with rectangular holes with a size of 3.0mm*4.0mm, and the dense fabric surface 11 has no pores.

[0023] Specifically, as shown in the figure, Figure 11 The sparse fabric surface 13 is covered with a hot melt non-woven fabric 31 and a plain cloth 32 for packaging, the hot melt non-woven fabric 31 used is a polyamide (PA) hot melt non-woven fabric with a thickness of 0.2mm. The plain cloth 32 used is a basalt fiber plain cloth.

[0024] Specifically, the geopolymer matrix 2 includes fly ash, silica ash, blast furnace slag, magnesium oxide (MgO), calcium oxide (CaO) and alkali activator, the fly ash used is grade I fly ash, the total mass fraction of SiO2, Al2O3 and Fe2O3 in the fly ash is greater than 70%, and the particle size is 0.1-100μm. The silica ash used is grade 90, and the mass fraction of SiO2 in the silica ash is greater than 90%. The blast furnace slag used is grade 95, the total mass fraction of SiO2, Al2O3 and CaO in the blast furnace slag is greater than 70%, the specific surface area is greater than 400m 2 / kg, and the particle size is 0.1-50μm. The alkali activator used is zero water sodium metasilicate with a modulus of 1.0.

[0025] Specifically, the matrix ratio in the flexible rapid hardening cement blanket is as follows: fly ash: silica ash: blast furnace slag: magnesium oxide (MgO): calcium oxide (CaO): alkali activator = 35:15:85:4:4:26.

[0026] The determination method includes the following steps: S1. Conduct field tests, lay the flexible rapid hardening cement blanket pavement structure on the soft soil foundation to be predicted, and select a typical vehicle for traffic test to illustrate the feasibility of the flexible rapid hardening cement blanket as a temporary pavement.

[0027] In this embodiment, the sand foundation of the port wind-blown sand section is selected as the soft soil foundation to be predicted, a 50t full load quality earthmoving vehicle is selected as the test vehicle, the flexible rapid hardening cement blanket pavement structure is laid on the soft soil foundation to be predicted and reciprocating traffic test is conducted to illustrate the feasibility of the flexible rapid hardening cement blanket as a temporary pavement, and the cumulative settlement of the pavement is recorded after a certain number of cycles. The deformation mode of the flexible rapid hardening cement blanket pavement in the field test is that the lane appears obvious depression, and the adjacent non-lane area will have a certain degree of local uplift. In addition, the test results show that after 10 times of vehicle reciprocating traffic, the cumulative settlement of the pavement reaches 12.1cm.

[0028] S2. According to the macrostructure of the cement carpet and the material property test of the concrete and the fabric, and by investigating the characteristic parameters of the foundation soil to be predicted, a flexible rapid-hardening cement carpet pavement and a natural foundation finite element model are constructed by using ABAQUS, the model is adjusted by using the field test results, and the accuracy of the model is verified.

[0029] In this embodiment, the flexible rapid-hardening cement carpet model is simplified into three parts of concrete (geopolymer matrix), dense fabric surface and sparse fabric surface, and a simplified finite element model structure diagram is shown in Figure 2 The concrete plastic damage model provided by ABAQUS is used as the concrete material model, and the corresponding material property test is carried out according to the model requirements to obtain the related parameters; the fabric is regarded as an orthotropic plate model, and the constitutive relation of the fabric is established; the Mohr-Coulomb model in ABAQUS is used to simulate the stress-strain relationship of the sandy soil foundation.

[0030] Specifically, the mechanical performance indicators of the concrete are shown in Table 1:

[0031] Specifically, the mechanical performance indicators of the fabric are shown in Table 2: Table 2 Mechanical performance indicators of fabric

[0032] Specifically, the mechanical performance indicators of the sandy soil are shown in Table 3: Table 3 Mechanical performance indicators of sandy soil

[0033] In this embodiment, the ABAQUS software is used to construct a pavement on the foundation to be measured in accordance with the actual proportion of the field test, and local mesh refinement is carried out in the area directly affected by the wheel load, and a mesh and overall model diagram is shown in Figures 3-5 The VDload subprogram in ABAQUS software is used to program the vehicle load in accordance with the actual situation, and the vehicle load is connected to the finite element model for calculation; the numerical simulation calculation result is shown in Figure 6 The simulation result shows that the pavement settlement amount reaches 12.8 cm after 10 cycles, by comparing the pavement settlement amount of the field vehicle passing through 10 times with the numerical simulation result, and comparing the deformation mode of the field test and the finite element model, the accuracy of the finite element model is verified.

[0034] S3. The VDload subprogram in ABAQUS software is used to code and connect the vehicle load to the finite element model for calculation, and the relationship between the pavement settlement amount and the vehicle load, the vehicle speed and the pavement thickness is established; In this embodiment, for simplifying calculation, the vehicle load q The maximum value of the stress of each wheel of the vehicle acting on the ground is selected, and the VDload subroutine is used to write the code of the vehicle load q , that is, the tire is regarded as a rectangular plate and its size is defined, and the rectangular plate is written into the ABAQUS finite element software, so that it moves along the rut in the finite element model at a certain speed, and the time-history curve of the deformation of the center point of the pavement rut is output, as shown in Figure 7 , and the maximum displacement is the maximum pavement settlement q caused by the vehicle driving on the pavement h 0. The calculation formula of the stress q is as follows:

[0035] wherein, F represents the concentrated force acting on the tire, A represents the contact area of the tire and the ground, B represents the tire ground contact width, L represents the tire ground contact length, if F or A is unknown, q it can be approximately taken as the tire pressure.

[0036] The pavement thickness is selected as 10 mm / 20 mm / 30 mm / 50 mm, and the vehicle speed is selected as 10 mph / 20 mph / 30 mph / 50 mph for permutation and combination, a total of 16 groups of working conditions, different vehicle loads are set on the 16 groups of working conditions, and the pavement settlement is recorded, several groups of loads can be selected for calculation to obtain the complete vehicle load q and settlement h 0 relationship curve. In the simulation, the moving speed of the vehicle load v and the thickness of the cement blanket pavement model t can be changed, and then the settlement of the rectangular plate model under different working conditions when moving on the lane is obtained.

[0037] Specifically, taking the pavement thickness t of 20 mm and the vehicle speed v of 30 mph as an example, the calculation result of this embodiment is shown in Table 4. Table 4 Relationship between wheel load q and pavement settlement h 0 (working condition: h = 20 mm, v = 30 mph) t v

[0038] ​​In this embodiment, a vehicle load-pavement settlement expression is established based on the calculation results of 16 groups of working conditions:

[0039] wherein, q represents the wheel-pavement interaction stress, h 0 represents the maximum pavement settlement caused by the tire interaction stress, k , n represents a control parameter related to the vehicle speed and the pavement thickness, and 16 groups of control parameters are obtained by fitting the 16 groups of working conditions k , n . Taking the pavement thickness of 20 mm t and the vehicle speed of 30 mph v as examples, a comparison chart of the vehicle load-pavement settlement relationship curve of this embodiment and the fitting curve is shown (see Figure 8 ).

[0040] Specifically, the fitting results of the control parameters k , n are shown in Table 5: Table 5 Fitting results of control parameters k , n

[0041] In this embodiment, the expressions of the control parameters k , n about the vehicle speed v and the pavement thickness t are respectively established:

[0042]

[0043] wherein, a k , b k , c k , d k , e k , g k , j k , a n , b n , c n , d n ,​e n , g n , j n are fitting parameters.

[0044] Specifically, the specific fitting parameter results of the embodiment are shown in Table 6: Table 6 Results of fitting parameters

[0045] Therefore, the relationship between the road subsidence amount and the vehicle load, the vehicle speed and the road thickness can be expressed by the following formula:

[0046] S4. The vehicle passability discrimination formula of the flexible rapid-hardening cement blanket pavement is determined by borrowing the emergency road passability judgment theory analysis, and then the vehicle passability performance of the flexible rapid-hardening cement blanket pavement based on the to-be-predicted soil body is determined according to the discrimination formula.

[0047] In the embodiment, the interaction among the tire, the road and the soil body is simplified, and the horizontal tension is assumed to be 0, specifically, as shown in the tire force analysis, the driving force of the ground to the tire Figure 9 is: P

[0048] wherein, μ is the adhesion coefficient between the tire and the road, and is usually taken as 0.05-0.2 on poor soil body, and is taken as 0.15 on sandy soil foundation in the example; F is the concentrated force acting on the tire; As shown in Figure 9 , the tire radius is R , the maximum subsidence amount caused by the wheel driving on the road is h 0, the maximum contact angle with the road is θ 0, and the following formula is:

[0049] The reaction force of the road and the foundation on the wheel on the contact surface is N , and the horizontal component thereof is the rolling resistance of the wheel R f , and the vertical component thereof is balanced with the concentrated force of the tire F , the unit arc length of the tire on the contact surface is Rdθ , and the unit area reaction force of a certain point on the contact surface is represented by σ , B , which represents the ground contact width of the tire, and thus the following expression can be established: ​

[0050] wherein, R f represents the rolling resistance of the tire to overcome the deformation of the road surface; Specifically, the unit area reaction force of a certain point σ The normal unit action stress of the tire at the same depth as the point s are equal, assuming the depth of the point is h According to the simplified Bekker theory, s can be expressed as s = kh n Thus, the rolling resistance of the tire to overcome the deformation of the road surface Expression:

[0051] The size of the tire driving force P and the rolling resistance R f , both divided by the concentrated force F (F = qBL) and subtracted, thus simplified to obtain the passing ability discrimination formula of the cement blanket road surface:

[0052] wherein, L is the ground length of the tire, which can be approximately expressed as:

[0053] wherein, R represents the tire radius.

[0054] The above formula is integrated, thus the passing ability discrimination formula of the cement blanket road surface can be deduced:

[0055] wherein, when Π is greater than 0, it is considered that the vehicle can pass, and when Π is less than or equal to 0, it is considered that the vehicle cannot pass.

[0056] The embodiment is based on a flexible rapid hardening cement carpet pavement vehicle passing performance determination method. According to the discriminant, the passing capacity of the flexible rapid hardening cement carpet pavement structure on the foundation to be tested for different vehicles can be efficiently and accurately inferred. The cement carpet pavement thickness required based on the actual traffic situation can also be back calculated according to the discriminant, which has important significance for solving the traffic problem in emergency situations. The determination method includes but is not limited to sandy soil foundation and is suitable for vehicle passing performance determination of temporary pavement structures laid on various soft foundations. Users can adjust and change the foundation and temporary pavement structure according to their own needs and calculate the vehicle passing capacity of the target working condition according to the above determination method.

[0057] The compressive strength and flexural strength of the cement carpet pavement structure sample in the embodiment are shown in Table 7: Table 7 Compressive strength and 7d flexural strength of the cement carpet pavement structure sample in the thickness direction

[0058] According to the provisions in the Technical Specification for Construction of Highway Cement Concrete Pavement that the 3d flexural strength of the pavement for heavy traffic shall not be less than 4.0 MPa, the flexural strength of the flexible rapid hardening cement carpet provided in the embodiment at 90 min has fully met the requirements, which shows that the cement carpet has high strength potential and flexibility, greatly improves the construction efficiency and can meet the needs of various emergency scenarios. Users can design different matrix ratios and raw materials according to different use scenarios to achieve the purpose.

[0059] Embodiment 3 The flexible rapid hardening cement carpet pavement structure includes a three-dimensional spacer fabric, a geopolymer matrix and an encapsulating material. The geopolymer matrix includes fly ash, silica fume, blast furnace slag, magnesium oxide (MgO), calcium oxide (CaO) and alkali activator. The three-dimensional spacer fabric includes a dense woven surface, spacer yarn and a sparse woven surface. The matrix ratio in the flexible rapid hardening cement carpet is as follows: fly ash: silica fume: blast furnace slag: magnesium oxide (MgO): calcium oxide (CaO): alkali activator = 30:15:85:4:4:20.

[0060] The construction is convenient and fast, and has the characteristics of flexible rapid hardening. The product has short setting time and fast strength development. Under natural curing conditions, the setting time is about 30 min, the 3h compressive strength is ≥20 MPa and the 3h flexural strength is ≥7 MPa. The excellent adaptability and rapid response capability in emergency situations such as earthquakes, heavy rains and landslides enable the cement carpet pavement structure to be used for rapid transportation of materials. In addition, it provides an innovative and efficient solution for rapid pavement laying in complex geographical environments such as mountain paths, desert areas and tidal areas.

[0061] The application establishes a connection between the characteristic parameter capable of expressing the relationship between the vehicle load and the amount of subsidence, the pavement thickness and the vehicle speed, can efficiently and accurately predict the passing performance of the temporary pavement structure under different vehicle loads on the foundation to be predicted, and greatly improves the efficiency and safety when the temporary pavement is used for emergency traffic guarantee.

[0062] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each of the embodiments mainly describes the difference from other embodiments.

[0063] The above only describes the preferred embodiments of the application and is not used to limit the application, and any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

[0064] The unmentioned part of the application is applicable to the prior art.

Claims

1. A method for determining vehicle passing performance of a flexible rapid-hardening cement carpet pavement based on ABAQUS, characterized in that, The method applied to the flexible rapid hardening cement blanket comprises the following contents: The finite element model of the flexible rapid hardening cement blanket pavement and the natural foundation is constructed by using ABAQUS software; Based on the finite element model, the maximum value of the acting stress of each wheel of the vehicle on the ground is selected as the vehicle load q The maximum road surface settlement caused by different vehicle loads in the driving process is obtained under different road surface thicknesses and vehicle speeds h 0; According to q = kh 0 n Fitting the vehicle load under different road surface thickness, vehicle speed working conditions q and the relationship between the amount of road subsidence h 0 k , n control parameters under different working conditions; According to k the data set consisting of the vehicle speed v , the road surface thickness t fitting, the control parameters k about the vehicle speed v and the road surface thickness t expression f k ( v , t ) is obtained; at the same time, according to n the data set consisting of the vehicle speed v , the road surface thickness t fitting, the control parameters n about the vehicle speed v and the road surface thickness t expression f n ( v , t ) is obtained; The passing ability discrimination formula of the flexible rapid hardening cement blanket pavement is: ， When Pi is greater than 0, it is considered that the vehicle can pass; when Pi is less than or equal to 0, it is considered that the vehicle cannot pass; wherein Π is a passability criterion; μ is the adhesion coefficient between the tire and the road surface; q is the vehicle load, R denotes the tire radius.

2. The method according to claim 1, characterized in that The finite element model of the flexible rapid hardening cement blanket pavement and the natural foundation is constructed by using ABAQUS, comprising: A1. The flexible rapid hardening cement blanket model is simplified into three parts of concrete, dense woven surface and sparse woven surface; A2. The concrete plastic damage model provided by ABAQUS is used as the concrete material model, and the corresponding material property test is carried out according to the model requirements to obtain the related parameters; A3. The woven fabric is regarded as an orthotropic plate model, and the constitutive relation of the woven fabric is established; A4. The Mohr-Coulomb model in ABAQUS is used to simulate the stress-strain relationship of the natural foundation soil to be predicted.

3. The method according to claim 1, characterized in that The accuracy of the finite element model is adjusted and verified by using the field test results, comprising: B1. The pavement laid on the foundation to be measured is constructed by using ABAQUS software, which is consistent with the actual proportion of the field test; B2. The vehicle load consistent with the actual situation is programmed by using the VDload subprogram in ABAQUS software, and the vehicle load is connected to the finite element model for calculation; B3. The pavement settlement amount of the vehicle passing back and forth 10 times in the field is compared with the numerical simulation result, so as to adjust the model and verify the accuracy of the finite element model, so that the numerical simulation result is infinitely close to the measured data.

4. The method according to claim 3, characterized in that The model is adjusted, comprising the following steps: C1. The parameter value range of the foundation soil to be measured required by ABAQUS software is determined through literature research; C2. The model is adjusted according to the rut depth development curve of the field test result, and the parameters of the foundation model are adjusted and inverted for multiple rounds based on the parameter value range of the foundation soil to be measured, until the satisfactory simulation accuracy is obtained; C3. If the simulation result is not accurate, the local mesh is refined in the area directly affected by the wheel load; C4. For the interface between the pavement layer and the foundation layer, the binding contact is usually used, and the interlayer slip and friction contact can be considered to improve the accuracy of the model.

5. The method of claim 1, wherein, The flexible rapid-hardening cement mat comprises a three-dimensional spacer fabric, a geopolymer matrix and an encapsulating material, the coefficient of adhesion between the tyre and the road surface on soft ground According to the discrimination formula, the thickness of the cement blanket pavement required to be laid based on the actual traffic situation can be deduced; or the user can adjust and change the foundation and temporary pavement structure according to his own needs, and calculate the vehicle passing capacity of the target working condition according to the above determination method. is 0.05-0.2; when analysing the interaction between the tyre, the road surface and the soil, the horizontal tension of the cement mat road surface is assumed to be 0.

6. The method of claim 1, wherein, The method is suitable for the vehicle passing ability determination of the temporary pavement structure laid on various soft foundations, including sandy soil, silt and other foundations.

7. The method of claim 1, wherein, The flexible rapid hardening cement blanket is determined whether it meets the passing ability requirement by using the determination method of claim 1, comprising three-dimensional spacer fabric, geopolymer matrix and packaging material; wherein the geopolymer matrix comprises fly ash, silica fume, blast furnace slag, magnesium oxide, calcium oxide and alkali activator; the three-dimensional spacer fabric comprises dense woven surface, spacer yarn and sparse woven surface.

8. A flexible rapid hardening cement mat pavement structure characterized by, ​ 9. The flexible rapid setting cement blanket of claim 8, wherein, Under natural maintenance conditions, the setting time is about 30 min, the 3h compressive strength is greater than or equal to 20 MPa, and the 3h flexural strength is greater than or equal to 7 MPa; the excellent adaptability and rapid response capability under emergency conditions such as natural disasters such as earthquakes, heavy rains, landslides, etc., the cement blanket can be used for rapid transportation of materials, and can be rapidly laid in complex geographical environments such as mountainous areas, desert areas, and beach areas.

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