CN113642083A - Special-shaped splicing design method for new and old roads - Google Patents
Special-shaped splicing design method for new and old roads Download PDFInfo
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Abstract
The invention discloses a special-shaped splicing design method for new and old roads, which comprises the following steps: establishing a two-dimensional model of a spliced cross section of a road, wherein the two-dimensional model comprises a road surface layer, a road foundation layer and a foundation layer, a geogrid is arranged at a lap joint junction of the road surface layer, the road foundation layer and the road surface layer are simulated by adopting a plane strain unit, the geogrid is simulated by adopting a rod unit, the foundation layer is simulated by adopting an infinite unit, and a finite element model is obtained; carrying out horizontal layered loading on the new roadbed layer and the new pavement layer to simulate horizontal layered filling in construction, and acquiring final deformation and stress simulation data in a construction stage; loading the final deformation and stress simulation data in the construction stage on a finite element model, and applying vehicle load to solve to obtain deformation and stress simulation data in the operation stage; and (3) changing the overlapping size of the pavement layer, the filling height of the new road base layer and the new pavement layer and the arrangement position of the geogrid, recalculating until the deformation and stress simulation data in the operation stage are lower than the deformation threshold and the stress threshold, and obtaining the optimal design data.
Description
Technical Field
The invention relates to the technical field of building construction, in particular to a special-shaped splicing design method for new and old roads.
Background
In the road splicing, reconstruction and widening and extension projects, newly-filled road base layers and road surface layers act on two sides or one side of old road base layers in a side-loading mode, the new and old road base layers and the road surface layers are spliced and combined into a whole, and interaction of the new and old road base layers and the road surface layers can be inevitably caused. Particularly, the splicing of the road surface layers of new and old roads is an important construction link, the technical requirements of the construction are relatively high, and once the splicing technology of the road surface layers is unqualified, various road surface layer diseases can be caused, so that the service life and the safety of the road are greatly reduced and lowered.
The structural strength of the new and old pavement layers is often very different, and the original structural design strength of the pavement layers is inferior to that of the new pavement layers due to the fact that the old pavement layers are low in design standards and construction levels many years ago. And through the load effect of heavy traffic for many years, the pavement layer structure has received the damage of certain degree for old pavement layer intensity often is less than newly-built pavement layer. Therefore, the characteristics of interaction of the new and old roadbed layers and the pavement layers in the construction process are known through simulation, the design scheme and the construction method of splicing and modifying or widening projects of roads are facilitated to be optimized, adverse factors generated by interaction of the new and old roadbed layers and the pavement layers are reduced, and the construction quality of the modified projects is guaranteed. However, the existing splicing of new and old road surface layers is designed with assistance by a finite element method in fewer cases.
Disclosure of Invention
In order to solve the problems, the invention discloses a special-shaped splicing design method for new and old roads, which comprises the following steps: step S1, establishing a two-dimensional model of a road splicing cross section, wherein the two-dimensional model comprises a road surface layer, a road foundation layer and a foundation layer from top to bottom, the road surface layer at least comprises a surface layer and a foundation layer from top to bottom, new and old road surface layers are connected in a lap joint mode, geogrids are arranged at lap joint junctions of the road surface layers, the two-dimensional model adopts a plane strain unit to simulate the road foundation layer and the road surface layer, a rod unit to simulate the geogrids, an infinite unit to simulate the foundation layer, material attributes are defined for the two-dimensional model, and meshes are divided to obtain a finite element model;
step S2, carrying out horizontal layered loading on a new roadbed layer and a new pavement layer of the finite element model to simulate horizontal layered filling in construction, and solving the finite element model to obtain final deformation and stress simulation data in a construction stage;
step S3, loading the final deformation and stress simulation data of the construction stage on the finite element model, applying vehicle load to the pavement layer of the finite element model, and solving the finite element model to obtain the deformation and stress simulation data of the operation stage;
and S4, changing the overlapping size of the pavement layer, the filling heights of the new roadbed layer and the new pavement layer and the arrangement position of the geogrid, returning to the step S2 until the deformation and stress simulation data in the operation stage are lower than the deformation threshold and the stress threshold, and obtaining the design data of the overlapping size of the pavement layer, the filling heights of the new roadbed layer and the new pavement layer and the arrangement position of the geogrid.
Optionally, the simulating a geogrid using a rod unit includes: the geogrid at the lap joint is horizontally and vertically decomposed into a plurality of rod units according to the lap joint step surface, the rod units are used as embedding areas in the PLAAXIS, the plane strain unit is used as a main area, the rod units are embedded into the plane strain unit, and the interface unit is used for simulating the contact between a pavement layer and the geogrid.
Optionally, the constitutive model of the geogrid is simulated using linear elastic constitutive equations.
Optionally, when the interface unit is used for simulating the mutual contact action of the road surface layer and the geogrid, the roughness of the contact surface of the road surface layer and the geogrid is reduced by a factor R according to the set interface strengthinterfaceAnd (3) simulating, wherein the interface strength reduction factor establishes an interface strength relation for the pavement layer and the geogrid according to the following equation:
wherein the content of the first and second substances,
is the rubbing angle of the contact surface;
Cinterfaceis the cohesive force of the contact surface;
Csoilthe cohesive force of the geogrid.
Optionally, the displacement function of any point in an infinite unit is:
in the formula:
N(3)(η)＝(1+η)(1-η)；
Uirepresenting the displacement component of the node i in the x direction, wherein x represents the width direction of the road in the horizontal plane;
Virepresenting the displacement component of the node i in the height direction of the vertical in-plane path;
ξ represents the width direction of the horizontal in-path in the local coordinate system;
η represents the height direction of the road in the vertical plane in the local coordinate system.
Optionally, the surface layer includes three structural layers of an upper surface layer, a middle surface layer and a lower surface layer, the base layer includes three structural layers of an upper base layer, a middle base layer and a lower base layer, and the arrangement position of the geogrid at least includes one condition among the structural layers of the lower base layer bottom, the upper base layer top, the lower surface layer top, the pavement layer and the pavement layer.
Optionally, in step S2, an initial ground stress field is further applied to the foundation layer, where the method of applying the initial ground stress field is to apply the soil body gravity of the old road foundation layer to the foundation layer, apply boundary constraint to the foundation layer, calculate the stress field of the foundation layer under the action of the soil body gravity, and then apply the obtained stress field load to the foundation layer.
Alternatively, a square load with a constant pitch is applied as the vehicle load on the pavement layer.
Optionally, the method for horizontally loading the load in layers is to horizontally divide the new roadbed layer and the new pavement layer into multiple filling layers according to a set time period, freeze all the filling layers, use each time period as a calculation process, activate the corresponding frozen filling layer in the corresponding calculation process from bottom to top, and then execute the calculation process.
Optionally, the side wall of the old base layer is coated with emulsified asphalt at the lap joint of the new and old pavement layers, and the geogrid is bonded with the new and old base layers by utilizing the viscosity formed after the emulsified asphalt is demulsified.
According to the invention, the splicing design of the new road surface and the old road surface can be effectively simulated by constructing the finite element model, so that optimized design data can be obtained through simulation calculation. The geogrid is simulated through the rod units, the contact effect of the geogrid and the soil body can be effectively simulated, a better simulation effect is obtained, and the geogrid is simulated through the rod units, so that the simulation calculation can be simplified. By simulating the foundation layer in an infinite unit, the amount of calculation can be reduced in the case of obtaining the foundation layer data.
Drawings
The above features and technical advantages of the present invention will become more apparent and readily appreciated from the following description of the embodiments thereof taken in conjunction with the accompanying drawings.
FIG. 1 is a schematic diagram illustrating a two-dimensional model of a roadway splice cross section in accordance with an embodiment of the present invention;
fig. 2 is a schematic view showing the laying of the geogrid of the embodiment of the present invention;
FIG. 3 is a schematic diagram of a wireless unit that represents an embodiment of the present invention;
fig. 4 is a node displacement vector diagram showing a road section according to an embodiment of the present invention.
Detailed Description
The embodiments of the present invention will be described below with reference to the accompanying drawings. Those of ordinary skill in the art will recognize that the described embodiments can be modified in various different ways, or combinations thereof, without departing from the spirit and scope of the present invention. Accordingly, the drawings and description are illustrative in nature and not intended to limit the scope of the claims. Furthermore, in the present description, the drawings are not to scale and like reference numerals refer to like parts.
A new and old road heterotype splicing design method is disclosed, heterotype means that indexes such as structural layer modulus, rigidity and thickness are different when new and old pavement structural layers are spliced, so that the integrity and stress continuity of splicing the new and old pavements are influenced, and the design method comprises the following steps:
step S1, establishing a two-dimensional model of a road splicing cross section, defining material properties, dividing grids, and obtaining a finite element model, wherein the two-dimensional model comprises a road surface layer 10, a road base layer 20 and a foundation layer 30 from top to bottom, the road surface layer at least comprises a surface layer and a base layer from top to bottom, new and old road surface layers are connected in a lap joint mode, and a geogrid 40 is arranged at a lap joint of the road surface layers. Fig. 1 shows a cross-sectional view of road widening, wherein the middle is an old road surface, and the two sides of the old road surface are widened, so that geogrids are arranged at splicing junctions of the two sides of the old road surface. As can be seen from fig. 1, the thickness of the old and new pavement layers is different when they are spliced. The two-dimensional model adopts a plane strain unit to simulate a roadbed layer and a pavement layer, adopts a rod unit to simulate a geogrid and adopts an infinite unit to simulate a foundation layer.
The geogrid is a novel high-strength geosynthetic material, after the geogrid is paved, the geogrid and filling material particles are enabled to be in friction and particle occlusion action, the filling material acts on passive resistance of grid ribs, the lateral sliding deformation of the filling material is limited, the bending resistance and the shearing resistance of the filling material are enhanced, namely, the bearing capacity and the lateral sliding resistance of the filling material are improved, meanwhile, a stress effect is generated between the geogrid and the filling material particles, partial vertical stress and horizontal stress of a partial structure layer are borne by the tension of the geogrid under the action of upper load, the load stress is uniformly diffused to a larger range, longitudinal cracks caused by stress concentration are reduced, and the integrity of a pavement structure layer is enhanced.
The following describes in detail how to simulate a road splice cross section using planar strain cells, rod cells, infinite cells.
Because the road base layer and the road surface layer have larger lengths, the road base layer and the road surface layer can be used as a plane strain problem to be calculated and analyzed, and parameter entity units with higher calculation precision, such as 4-node or 8-node plane strain and the like, can be adopted to solve, for example, a plane strain unit provided in a PLAAXIS (finite element analysis software for geotechnical engineering) program.
The two-dimensional model simulates the geogrid by using the rod units, and specifically, the geogrid at the lap joint is horizontally and vertically decomposed into a plurality of rod units according to the step surfaces at the lap joint, such as two horizontal rod units and one vertical rod unit in fig. 2. In the PLAAXIS program, the rod unit is embedded in the planar strain unit by using the rod unit as an embedded area and the planar strain unit as a main area. Through decomposing geogrid into level and vertical pole unit, can simulate geogrid and the road surface layer under the road surface layer atress condition with the road surface layer under the contact action pull pressure and the crooked condition to know geogrid to the enhancement effect of road surface layer. For the contact between the road surface layer and the geogrid, an interface unit in the PLAAXIS is adopted for simulation, the geogrid can reduce differential settlement at the splicing position of a new road and an old road, the tensile strength of the geogrid is good, the tensile strength of the geogrid is very high, the tensile force applied to the geogrid is smaller than the tensile strength of the geogrid under the ordinary condition, the stress-strain relation of the geogrid is still in an elastic stage, and therefore the constitutive relation of the geogrid can be regarded as linear elasticity, and the constitutive model of the geogrid is subjected to simulation analysis by adopting a linear elasticity constitutive equation.
When the interface unit is used for simulating the mutual contact action of the road base layer, the road surface layer and the geogrid, the roughness of the contact surface of the road base layer, the road surface layer and the geogrid can be reduced by a factor R according to the set interface strengthinterfaceTo be simulated. This parameter may establish an interfacial strength relationship for the road base layer, the road surface layer structure layer, and the geogrid according to the following equation:
wherein the content of the first and second substances,
is the rubbing angle of the contact surface;
Cinterfaceis the cohesive force of the contact surface;
Csoilthe cohesive force of the geogrid.
In general, where the base course, the pavement layer and the geogrid interact, the pavement layer is stronger than the geogrid, so Rinterface<1, determining the interfacial strength reduction factor R of the contact surface of the roadbed layer, the pavement layer and the geogridinterface＝0.9。
The two-dimensional model adopts an infinite unit to simulate a foundation course, a road is a banded space geometric body, and the foundation course is connected with the foundation course and can be regarded as a semi-infinite space body. In the finite element analysis process, since the complete calculation and analysis cannot be performed on the semi-infinite space range, and only a certain range near the roadbed layer can be taken for the approximate calculation, the influence on the part outside the calculation region cannot be considered. The use of infinite elements to take into account the parts outside the calculation area, combined with finite elements, makes the calculation result closer to reality. Therefore, the geogrid, the pavement layer and the roadbed layer adopt the limited units, and the foundation layer uses the unlimited units, so that the limited units and the unlimited units are combined, and a better effect can be achieved. Meanwhile, the number of units can be reduced on the premise of not influencing the calculation precision by adopting an infinite unit on the boundary connected with the infinite domain compared with a finite unit, so that the calculation workload is reduced.
As shown in fig. 3, the infinite unit is a 9-node two-dimensional infinite unit, in which nodes No. 1, 3, and 5 are coupled to the plane finite unit, nodes No. 2, 4, and 6 are intermediate nodes of the infinite unit, and three nodes 7, 8, and 9 are at infinity.
The infinite unit is the mapping from the finite field in the local coordinate system to the infinite field in the whole coordinate system, namely when the local coordinate is xi → 1, the corresponding whole coordinate tends to infinity, thereby realizing that the calculation range extends to an infinite point; secondly, the description of the displacement attenuation process in an infinite domain, namely xi → 1, the displacement tends to be zero, thereby realizing the boundary condition that the displacement at infinity is zero. Thus, with infinite cells as the boundary of the semi-infinite domain problem, a suitable displacement function can be selected that satisfies the two conditions of zero displacement decay for points at infinity, and a calculated value of displacement equal to the value of the adjacent finite cell at the boundary of the cell.
The displacement function for any point in the infinite unit is:
in the formula:
N(3)(η)＝(1+η)(1-η)；
Uirepresenting the displacement component of the node i in the width direction of the path in the horizontal plane;
Virepresenting the displacement component of the node i in the height direction of the vertical in-plane path;
ξ represents the displacement in the width direction of the horizontal in-path in the local coordinate system;
η represents the displacement in the height direction of the road in the vertical plane in the local coordinate system.
And setting material properties including gamma, c, phi, E, K0, mu and k for the two-dimensional model, and determining calculation parameters of various materials in the calculation region to select according to the table I.
And step S2, carrying out horizontal layered loading on the new roadbed layer and the new pavement layer of the finite element model to simulate horizontal layered filling in construction, and solving the finite element model to obtain deformation and stress simulation data in the construction stage. And calculating the load step of each layer by taking the stress and displacement obtained by the previous step as an initial stress field and an initial displacement field of the layer until the deformation and stress simulation data of the final construction stage after construction is finished are obtained. The stress field and the displacement field of the new road surface layer and the new road base layer are obtained by gradually superposing the stress field and the displacement field due to the gradual influence of the construction process when the construction process is finished, and the development process of the stress and the strain of the new road base layer and the new road surface layer by layer filling is well simulated.
The method for loading the load horizontally and hierarchically comprises the steps of dividing time periods and filling heights according to actual hierarchical filling conditions in construction engineering, freezing all filling layers, taking each time period as a calculation procedure, activating the corresponding frozen filling layer in the corresponding calculation procedure from bottom to top, and then executing the calculation procedure.
Setting the calculation area after the i-1 st layer is filled, and respectively representing the displacement, the strain and the stress of the nodes in the calculation area as omegai-1、{ui-1}、{εi-1}、{σi-1And after the ith layer is filled, the calculation area is changed into omegaiAnd assume that omega is due to level i filliLoad increase of nodes within a domain [ Δ p ]iAt stress boundary SσUp to cause an increase in the surface force of the node { Δ q }iThereby causing an increase in displacement, strain and stress of { Δ u }i}，{Δεi}，{ΔσiGet the calculation result after the i-th layer is filled as
{ui}＝{ui-1}+{Δui}
{εi}＝{εi-1}+{Δεi}
{σi}＝{σi-1}+{Δσi}
And (3) along with the layered filling process, each layer is loaded to calculate a unit rigidity matrix and a unit node stress matrix which are used for reconstructing the soil body. After the completion of filling, the deformation and stress states of the roadbed layer and the pavement layer are respectively
In the formula, { σ0Is the initial stress state of the soil body, and { u }0}，{ε0The corresponding displacement and strain states. Assuming no temperature and no shrinkage deformation due to capillary pressure in the soil, { u }0And e0All shall be zero. j denotes a total of j layers of fill.
The process of forming the unit rigidity matrix and the unit node stress matrix of the soil body is as follows:
the cell strain formula is expressed by node displacement:
{ε}＝{B}{u}e
where { ε } is the cell strain vector;
{ B } is a cell strain matrix;
{u}eis a unit displacement vector, containing all node displacement components of the unit.
Obtaining a unit stress formula expressed by node displacement by using a physical equation and a unit strain formula:
{σ}＝{D}{B}{u}e
where, { σ } is the unit stress vector;
{ D } is the elastic matrix.
Establishing a relationship between nodal forces acting on the elements and nodal displacements using the principle of virtual work, i.e. a finite element equation set
[K]e{u}e＝{P}e
Wherein [ K ]]eFor the cell stiffness matrix, { P }eIs a cell node load matrix.
The finite element equation set can be solved by an iterative method or other methods, so that the displacement, strain and stress simulation data in the construction stage can be obtained. The finite element equation set can be established by using software PLAAXIS, and the finite element equation set can be automatically established and solved by establishing a two-dimensional model in the PLAAXIS, setting material properties, adding constraints and loading loads.
And step S3, loading the final deformation and stress simulation data in the construction stage on the finite element model, applying vehicle load to the road surface layer of the finite element model, and solving the finite element model to obtain the strain and stress simulation data in the operation stage. For example, fig. 4 is a node displacement vector diagram of a road section.
In order to facilitate the analysis and calculation of finite elements, the double-circle vertical uniform load in the design specification of the road asphalt pavement layer is simplified into a mode of replacing a double-circle load by a 19cm multiplied by 19cm square load with a constant interval, a double-wheel set single axle load of 100kN is taken as a standard axle load of the urban main road, and a double-wheel set single axle load of 80kN is taken as a standard axle load of the urban branch road. The calculated parameters for the standard axle load were determined according to the following table.
Watch two
And step S4, changing the overlapping size of the pavement layer, the filling heights of the new roadbed layer and the new pavement layer and the arrangement position of the geogrid, returning to the step 2 until the deformation and stress simulation data in the operation stage are lower than the deformation threshold and the stress threshold, and obtaining the design data of the overlapping size of the pavement layer, the filling heights of the new roadbed layer and the new pavement layer and the arrangement position of the geogrid. The arrangement position of the geogrid can be at least one of the bottom of the lower base layer, the top of the upper base layer, the top of the lower base layer or among all structural layers of the surface layer.
Further, an initial ground stress field is also applied to the foundation layer, and as the foundation layer uses infinite units, no constraint in any direction is applied, the initial stress field is applied to achieve the balance of forces.
The method for applying the initial ground stress field on the foundation course is to apply the soil body gravity of the old road foundation course on the foundation course, apply boundary constraint on the foundation course, calculate the stress field of the foundation course under the action of vertical pressure, and then apply the obtained stress field load on the foundation course (at this time, the boundary constraint is not applied on the foundation course, but the initial stress field is used for realizing the force balance), thus obtaining the initial stress field which not only meets the balance condition, but also does not violate the yield criterion and has zero displacement.
Wherein a lateral pressure coefficient K can be applied0And establishing a relation between the horizontal stress and the vertical stress (soil body gravity), thereby calculating the horizontal stress generated when the soil body gravity is applied to the foundation layer. Lateral pressure coefficient K0Theoretically, the calculation is performed as follows,
alternatively, the calculation may be performed by applying the following equation according to the properties of the soil.
Normally consolidating sandy soil:
normally consolidating the cohesive soil:
ultra-consolidation of soil:
in the formula: μ -poisson's ratio of soil;
OCR-the ultra-consolidation ratio of soil.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A special-shaped splicing design method for new and old roads is characterized by comprising the following steps:
step S1, establishing a two-dimensional model of a road splicing cross section, wherein the two-dimensional model comprises a road surface layer, a road foundation layer and a foundation layer from top to bottom, the road surface layer at least comprises a surface layer and a foundation layer from top to bottom, new and old road surface layers are connected in a lap joint mode, geogrids are arranged at lap joint junctions of the road surface layers, the two-dimensional model adopts a plane strain unit to simulate the road foundation layer and the road surface layer, a rod unit to simulate the geogrids, an infinite unit to simulate the foundation layer, material attributes are defined for the two-dimensional model, and meshes are divided to obtain a finite element model;
step S2, carrying out horizontal layered loading on a new roadbed layer and a new pavement layer of the finite element model to simulate horizontal layered filling in construction, and solving the finite element model to obtain final deformation and stress simulation data in a construction stage;
step S3, loading the final deformation and stress simulation data of the construction stage on the finite element model, applying vehicle load to the pavement layer of the finite element model, and solving the finite element model to obtain the deformation and stress simulation data of the operation stage;
and S4, changing the overlapping size of the pavement layer, the filling heights of the new roadbed layer and the new pavement layer and the arrangement position of the geogrid, returning to the step S2 until the deformation and stress simulation data in the operation stage are lower than the deformation threshold and the stress threshold, and obtaining the design data of the overlapping size of the pavement layer, the filling heights of the new roadbed layer and the new pavement layer and the arrangement position of the geogrid.
2. The method for designing the irregular splicing of the new road and the old road according to claim 1,
adopt pole unit simulation geogrid, include: the geogrid at the lap joint is horizontally and vertically decomposed into a plurality of rod units according to the lap joint step surface, the rod units are used as embedding areas in the PLAAXIS, the plane strain unit is used as a main area, the rod units are embedded into the plane strain unit, and the interface unit is used for simulating the contact between a pavement layer and the geogrid.
3. The method for designing the irregular splicing of the new road and the old road according to claim 1,
the constitutive model of the geogrid is simulated by adopting a linear elasticity constitutive equation.
4. The method for designing the irregular splicing of the new road and the old road according to claim 2,
when the interface unit is used for simulating the mutual contact action of the pavement layer and the geogrid, the roughness of the contact surface of the pavement layer and the geogrid is reduced by a factor R according to the set interface strengthinterfaceAnd (3) simulating, wherein the interface strength reduction factor establishes an interface strength relation for the pavement layer and the geogrid according to the following equation:
wherein the content of the first and second substances,
is the rubbing angle of the contact surface;
Cinterfaceis the cohesive force of the contact surface;
Csoilthe cohesive force of the geogrid.
5. The method for designing the irregular splicing of the new road and the old road according to claim 1,
the displacement function for any point in the infinite unit is:
in the formula:
N(3)(η)＝(1+η)(1-η)；
Uirepresenting the displacement component of the node i in the x direction, wherein x represents the width direction of the road in the horizontal plane;
Virepresenting the displacement component of the node i in the height direction of the vertical in-plane path;
ξ represents the width direction of the horizontal in-path in the local coordinate system;
η represents the height direction of the road in the vertical plane in the local coordinate system.
6. The method for designing the irregular splicing of the new and old roads as claimed in claim 1, wherein the surface layer comprises three structural layers of an upper surface layer, a middle surface layer and a lower surface layer, the base layer comprises three structural layers of an upper base layer, a middle base layer and a lower base layer, and the arrangement position of the geogrid at least comprises one condition among the structural layers of the lower base layer bottom, the upper base layer top, the lower surface layer top, the road surface layer and the road base layer.
7. The method for designing the irregular splicing of the new road and the old road according to claim 1,
in step S2, an initial ground stress field is further applied to the foundation layer, and the method for applying the initial ground stress field is to apply the soil body gravity of the old road foundation layer to the foundation layer, apply boundary constraint to the foundation layer, calculate the stress field of the foundation layer under the action of the soil body gravity, and then apply the obtained stress field load to the foundation layer.
8. The method for designing the irregular splicing of the new road and the old road according to claim 1,
and square loads with constant intervals are adopted as vehicle loads to be applied to the road surface layer.
9. The method for designing the irregular splicing of the new road and the old road according to claim 1,
the method for loading the load horizontally and hierarchically comprises the steps of horizontally dividing a new roadbed layer and a new pavement layer into a plurality of filling layers according to set time periods, freezing all the filling layers, taking each time period as a calculation procedure, activating the corresponding frozen filling layers in the corresponding calculation procedures from bottom to top, and then executing the calculation process.
10. The method as claimed in claim 1, wherein the side wall of the old and new road surface layer is coated with emulsified asphalt at the overlapping area, and the geogrid is bonded with the old and new road surface layer by using the viscosity of emulsified asphalt after emulsion breaking.
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