Fabricated cold conduction roadbed structure, construction method and design method

Abstract

The invention relates to the technical field of road subgrade construction, in particular to an assembled cold conduction subgrade structure, a construction method and a design method. According to the assembled cold conduction roadbed structure, heat, displaced from frozen soil in the foundation, of all the permanent hot bars can be discharged through the ventilation ducts of the corresponding assembled roadbed modules, so that the permanent hot bars are arranged below the transverse middle of the roadbed, the heat dissipation requirement of the permanent hot bars can also be met, uniform cooling can be achieved within the roadbed range, and the service life of the roadbed is prolonged. And the arrangement of the assembled roadbed module matched with the filling section does not influence the safety of roadbed construction and operation, and the assembled roadbed module is convenient to construct and high in efficiency. Before construction of the prefabricated cold conduction roadbed structure, energy balance in the whole process of construction and operation is considered, temporary hot rods are selectively arranged on the basis of the time required for complete freezing of a movable layer, complete freezing of a foundation is achieved before construction, and cold energy is stored in advance to balance thermal disturbance in the construction period and the operation period.

Description

Technical Field

[0001] The present invention relates to the technical field of road subgrade construction, and in particular to an assembled cooling subgrade structure, a construction method and a design method. Background Art

[0002] The permafrost area in my country is 2.15 million square kilometers, accounting for about a quarter of the country's total land area. It is mainly distributed in the Qinghai-Tibet Plateau, the Greater and Lesser Khingan Mountains in the northeast, and the western plateau. The permafrost in the Qinghai-Tibet Plateau, known as the "Roof of the World" and the "Third Pole of the World", is high-altitude permafrost. Its extremely harsh climate and geographical environment are the root causes that affect engineering construction. Therefore, road engineering in the Qinghai-Tibet Plateau shows obvious regional shortcomings and backward transportation network. In addition, affected by extreme high temperatures and rainfall events on the Qinghai-Tibet Plateau in recent years, the degradation of permafrost and glacier melting on the Qinghai-Tibet Plateau have significantly increased, and derivative geological disasters such as thermal melt landslides, glacial lake outbursts and thaw mudslides have intensified, posing greater challenges to the high-quality and safe operation of highways. Faced with technical difficulties in highway design and construction in the Qinghai-Tibet Plateau, design principles for protecting permafrost have been proposed for the construction of highways in permafrost areas. Heat rod roadbed has been widely used as an "active cooling measure" in permafrost roads. Relevant engineering monitoring data show that the cooling effect of the heat rod is very obvious. The ground temperature near the heat rod is lower than that of the natural hole and can remain stable for a long time, which plays a significant role in improving the stability of the roadbed.

[0003] In previous roadbed projects, heat rods were generally arranged on both sides of the roadbed, located in the middle of the shoulder or slope, and arranged at equal intervals along the longitudinal direction of the roadbed. However, as a cooling measure for point-shaped projects, the cooling range of heat rods is limited. Secondly, the previous layout of heat rods only considered the construction period. When the cold energy stored in the foundation cannot balance the heat released during the construction period, the heat rods also need to balance the heat released during the construction period in the first few years of the project operation, which will cause some unnecessary initial diseases. Therefore, it is necessary to adjust the layout method and layout range of heat rods from the perspective of energy balance in the whole process to reduce the temperature of frozen soil in the roadbed and a certain depth range. The Chinese patent with the announcement number CN106120506B discloses a method for designing parameters of heat rod roadbed in permafrost areas based on the principle of energy balance. It takes the construction period as the standard, calculates the structural parameters and layout spacing of the heat rods, and does not consider the operation period. That is, the heat rod design of the prior art does not consider the complete refrost period of the foundation, and only calculates the number of heat rods according to the refrost period required during the construction period. This will result in some foundation heat not being released and remaining in the operation period, that is, the construction period and the operation period are not considered together, which has an adverse impact on highway operations. The Chinese patent with the announcement number CN116657586B discloses a targeted focused heat rod array applied to the road-bridge transition section. It mentions the heat rod array, but only for the road-bridge transition section. The heat rods are arranged in a fan-shaped array according to a certain rule on one side of the roadbed near the abutment and pile foundation. Although it can achieve the effect of cooling the base, it fails to consider the energy balance.

[0004] Moreover, the heat rod arrays in the above-mentioned arrangement are on both sides of the roadbed, so that the heat rods can be directly exposed to facilitate heat dissipation of the heat rods; however, when the cold energy required in the foundation is large, relying solely on the method of setting up heat rod arrays on both sides of the roadbed cannot meet the corresponding cooling needs of the foundation. Since it is difficult to dissipate heat from the heat rods in the middle of the roadbed and it affects the construction of the roadbed, it is difficult to set up a heat rod array in the middle of the roadbed in the prior art. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem in the prior art that when the foundation below the roadbed is cooled by a heat rod array, the heat rod arrays are on both sides of the roadbed. The corresponding cooling demand of the foundation cannot be met by simply setting up heat rod arrays on both sides of the roadbed. In order to provide sufficient heat dissipation channels for the heat rods, reduce the impact on the roadbed body, and achieve rapid construction, an assembled cooling roadbed structure, construction method and design method are provided.

[0006] In a first aspect, the present invention provides an assembled cooling roadbed structure, comprising:

[0007] A bottom layer structure, wherein the bottom layer structure comprises a plurality of assembled roadbed modules and a plurality of filling sections, wherein the assembled roadbed modules are arranged transversely along the roadbed, and the assembled roadbed modules are spaced apart longitudinally along the roadbed, and the bottom of the assembled roadbed module is used to be embedded in the foundation, and the filling section is filled between two adjacent assembled roadbed modules in the longitudinal direction of the roadbed; a plurality of mounting holes are spaced apart at the bottom of the assembled roadbed module along the length direction of the assembled roadbed module, and a ventilation duct is arranged inside the assembled roadbed module along the length direction of the assembled roadbed module, wherein the ventilation duct is connected to all the mounting holes of the assembled roadbed module, and wherein the ventilation duct comprises an air inlet and an air outlet, and the air inlet and the air outlet can be connected to the outside of the roadbed;

[0008] An upper structure, the upper structure being arranged above the lower structure;

[0009] A heat rod array, wherein the heat rod array comprises a plurality of permanent heat rods, wherein the permanent heat rods are arranged in corresponding mounting holes, wherein the condensation section at the upper portion of the permanent heat rods extends into the corresponding ventilation duct, and the evaporation section at the lower portion of the permanent heat rods is used to extend below the upper limit of frozen soil in the foundation, and all the permanent heat rods are arranged in an array in the roadbed through the assembled roadbed module.

[0010] The assembled cooling roadbed structure of the present invention has a bottom structure that uses a filling section to fill in between two adjacent assembled roadbed modules in the longitudinal direction of the roadbed, so that the bottom structure is complete and the smooth installation of the upper structure is ensured; the filling section can adapt to the longitudinal deformation of the roadbed, thereby reducing the possibility of lateral dislocation of the assembled roadbed module and ensuring the integrity of the bottom structure during the longitudinal deformation of the roadbed; the bottom of the assembled roadbed module is used to be embedded in the foundation, which can further ensure the lateral and longitudinal position of the assembled roadbed module, thereby ensuring the stability of the structure and the safety of subsequent operation; the permanent heat rod is arranged in the corresponding installation hole at the bottom of the assembled roadbed module, the condensation section at the top of the permanent heat rod extends into the corresponding ventilation duct, and the evaporation section at the bottom of the permanent heat rod is used to extend below the upper limit of the frozen soil in the foundation. The ventilation duct is connected to all the mounting holes of the assembled roadbed module, and the ventilation duct includes an air inlet and an air outlet, and the air inlet and the air outlet can be connected to the outside of the roadbed, that is, all the heat displaced from the frozen soil in the foundation by the permanent heat rods can be discharged through the ventilation duct of the corresponding assembled roadbed module, so that the permanent heat rod can be set below the transverse middle part of the roadbed, and the heat dissipation of the permanent heat rod can also be met. Moreover, all the permanent heat rods can be arranged in an array in the roadbed through the assembled roadbed module, so that a larger number of permanent heat rods can be set, which is beneficial to provide more cold energy to the foundation, and uniform cooling can be achieved within the roadbed range. The setting of the assembled roadbed module will not affect the safety of roadbed construction and operation, and the construction of the assembled roadbed module is convenient and efficient.

[0011] Preferably, the cross section of the assembled roadbed module is square, rectangular or trapezoidal;

[0012] And / or, the cross-sectional shape of the ventilation duct is rectangular, circular, elliptical, etc.

[0013] Preferably, the assembled roadbed module comprises a bottom plate and an upper cover, the bottom plate is provided with the mounting holes at intervals along the transverse direction of the roadbed, the bottom plate is provided with mounting grooves at both sides along the longitudinal direction of the roadbed, the mounting grooves are arranged along the transverse direction of the roadbed, the mounting grooves on both sides are located at both sides of the mounting holes, the upper cover comprises a top plate and two side plates arranged at intervals along the longitudinal direction of the roadbed, the side plates can be adapted to be inserted into the mounting grooves on the corresponding sides, and the ventilation duct is formed between the bottom plate, the top plate and the two side plates; the assembled roadbed module is divided into a bottom plate and an upper cover, after the permanent heat rod is constructed, the bottom plate and the upper cover are constructed in sequence, the mounting holes on the bottom plate are convenient for aligning the permanent heat rod installation, and the side plates of the upper cover are convenient for aligning the mounting grooves on the bottom plate, so that the installation process is simpler and does not affect the function of the assembled roadbed module;

[0014] Or, the assembled roadbed module includes two trough members, the openings of the two trough members are arranged opposite to each other, the openings of the trough members are arranged along the longitudinal direction of the roadbed, and the bottoms of the two trough members are provided with a plurality of opposite semicircular notches, and the two opposite semicircular notches are combined to form the mounting hole. The assembled roadbed module uses two trough members, first aligns the constructed permanent heat rod through the semicircular notch of one trough member, and then installs the other trough member based on the trough member, which is more convenient to install and does not affect the function of the assembled roadbed module;

[0015] Preferably, a heat insulation board is provided on the top of the ventilation duct to reduce the ability of the upper structure to directly transfer heat into the foundation.

[0016] Preferably, at least two of the assembled roadbed modules are continuously arranged in the transverse direction of the roadbed, and two adjacent assembled roadbed modules in the transverse direction of the roadbed are connected to each other by grouting.

[0017] When the transverse dimension of the roadbed is large, at least two of the assembled roadbed modules are continuously arranged in the transverse direction of the roadbed to facilitate transportation and installation, and the two adjacent assembled roadbed modules in the transverse direction of the roadbed are connected to each other by grouting, which can achieve sealing of the two adjacent assembled roadbed modules in the transverse direction, making the ventilation duct continuous and the heat dissipation effect better.

[0018] Preferably, the air inlet and the air outlet are arranged at the end faces of the assembled roadbed module in the length direction, so as to form convection and achieve better heat dissipation effect;

[0019] And / or, the superstructure is provided with a cushion layer, a bidirectional geogrid and a pavement structure layer in sequence from bottom to top, the cushion layer and the pavement structure layer are provided with side slopes on both lateral sides, and the lateral spacing between the permanent heating rods installed on both lateral sides of the roadbed and the toe of the side slopes on the corresponding sides is not less than 0.5m;

[0020] And / or, the assembled roadbed module is made of one or a combination of reinforced concrete, construction solid waste, industrial solid waste and foamed concrete;

[0021] And / or, the filling section adopts one or a combination of fill soil, crushed stone and gravel; the effect of adapting to roadbed deformation is better.

[0022] In a second aspect, the present invention provides a method for constructing an assembled cooling roadbed structure, which is used to construct the assembled cooling roadbed structure, comprising the following steps:

[0023] S01. Level the site and mark the locations of all heating rods at the construction site; when the active layer is completely frozen back, the time required is t f The refrost time t is greater than the construction period requirement d The heat rods include several permanent heat rods and several temporary heat rods; when the active layer is completely frozen back, the time required is t f Less than or equal to the refrost time required by the construction period t d When, the heat rod includes a number of permanent heat rods;

[0024] S02. Install all the heat rods at the marked positions so that the evaporation ends of the heat rods are inserted below the upper limit of the frozen soil in the natural foundation;

[0025] S03, the time required for the active layer to completely freeze back f The refrost time t is greater than the construction period requirement d At t d After that, the temporary heating rods added during the construction period are removed, and the heating rod holes of the temporary heating rods are backfilled, and then the assembled roadbed modules are installed; when the active layer is completely thawed, the time required is t f Less than or equal to the refrost time required by the construction period t d At t f Then install the assembled roadbed module;

[0026] S04, construction filling section;

[0027] S05. Construct superstructure.

[0028] The method for constructing the assembled cooling roadbed structure of the present invention requires the time t required for the active layer to completely refreeze. f The thawing time t required by the construction period dBy comparing the above, temporary heat rods can be selected to dissipate heat from the foundation, which can accelerate the refrost of the foundation and meet the requirements of stable construction of the underlying structure and the upper structure during the construction period. The time required for the active layer to completely refrost is t f It is related to the operation period, that is, this method takes into account the energy balance of the entire process of the construction period and the operation period at the same time; and the assembled roadbed module has a high degree of assembly, good construction quality, and high construction efficiency; the temporary heat rods can be reused, which greatly reduces the project cost.

[0029] In a third aspect, the present invention provides a design method for the construction of an assembled cooling roadbed structure, which is used to guide the construction method of the assembled cooling roadbed structure, comprising the following steps:

[0030] S1: Calculate the annual heat transfer Q of the permanent heat rod under design conditions using the energy balance method 2 and the arrangement spacing of permanent heat rods s ; and calculate the cold energy required to completely refrozen the active layer of the natural foundation Q 1 ;

[0031] S2: Based on the annual heat transfer Q of the permanent heat rod 2 、The arrangement spacing of permanent heat rods s and the cold energy demand Q for complete refrigeration of the natural foundation active layer 1 Calculate the time t required for the active layer to completely refrozen f , the time required for the active layer to completely freeze back to its original state is t f The calculation formula is:

[0032]

[0033] S3: Determine the time t required for the active layer to completely refreeze f Is it greater than the refrost time t required during the construction period? d If yes, determine the number of temporary heating rods m and the center distance s of adjacent temporary heating rods to be added on the roadbed cross section during the construction period, and according to the permanent heating rod spacing s s , the number of temporary heating bars m on the cross section of the roadbed and the center spacing s of adjacent temporary heating bars guide the construction of permanent heating bars and temporary heating bars; if not, according to the permanent heating bar spacing s s Guidance on the construction of permanent hot rods.

[0034] The present invention provides a design method for the construction of the assembled cooling roadbed structure, which can calculate the time t required for the active layer to completely refreeze. f , and thus can meet the requirements of the construction period for the refrost time t d The comparison can provide guidance on whether to set up temporary heat rods when constructing the assembled cooling roadbed structure, which is conducive to ensuring the smooth construction of the assembled cooling roadbed structure.

[0035] Preferably, in step S1, the cooling energy required to completely refrozen the active layer of the natural foundation is Q 1 The calculation formula is:

[0036]

[0037] Where: n is the number of parts into which the active layer is divided, n≥1; i is the index; H i is the thickness of the i-th layer; W is the width between the slope toes on both sides of the embankment; ρ di is the dry density of the i-th layer; C i is the specific heat capacity of the i-th layer; T avgi is the average ground temperature of the i-th layer; T pci is the phase transition temperature of the i-th layer of soil; ω i is the water content of the i-th layer; ω iu is the unmoved water content of the i-th layer; L is the latent heat of crystallization of water or melting of ice.

[0038] The cold energy required to completely refrozen the above natural foundation active layer Q 1 The calculation formula for the cooling energy demand Q 1 The calculation is performed with high accuracy and small amount of calculation.

[0039] Preferably, in step S3, the effective radius s of the temporary heating rod during the construction period is calculated first. s ', effective radius of temporary hot rod during construction period s s The calculation formula of ' is:

[0040]

[0041] Where: Δt is the working time of the temporary heating rod in a year; t is the time variable; T s is the annual average ground temperature; T a is the annual average temperature; 0 is the outer diameter of the temporary hot rod; R a is the temporary heat rod thermal resistance; f is the thermal conductivity of the temporary heat rod fin; L e is the length of the evaporation section of the temporary hot rod;

[0042] Then according to the temporary hot rod effective radius s s 'Calculate the number of temporary hot rods m on the roadbed cross section. The calculation formula for the number of temporary hot rods m on the roadbed cross section is:

[0043]

[0044] Where: W is the width between the slope toes on both sides of the roadbed;

[0045] And according to the effective radius s of the temporary hot rod s' and the arrangement of the newly added temporary hot bars to calculate the center distance s between adjacent temporary hot bars;

[0046] When the layout of the newly added temporary heat rods is a square, s = s s ' / 1.128; When the layout of the newly added temporary heat rod is an equilateral triangle, s=s s ' / 1.05.

[0047] The above calculation method can quickly and accurately calculate the number m of temporary heating bars on the roadbed cross section that need to be added during the construction period and the center distance s of adjacent temporary heating bars, which is convenient for guiding the layout of temporary heating bars.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. The present invention provides an assembled cooling roadbed structure, wherein a permanent heat rod is arranged in a corresponding installation hole at the bottom of an assembled roadbed module, a condensation section at the upper part of the permanent heat rod extends into the ventilation duct corresponding to the assembled roadbed module, and an evaporation section at the lower part of the permanent heat rod is used to extend below the upper limit of the frozen soil in the foundation, the ventilation duct is connected to all the installation holes of the assembled roadbed module, the ventilation duct includes an air inlet and an air outlet, and the air inlet and the air outlet can be connected to the outside of the roadbed, that is, all the heat displaced from the frozen soil in the foundation by the permanent heat rod can be passed through The heat is discharged through the ventilation duct of the corresponding assembled roadbed module, so that the permanent heat rod can be set below the middle of the roadbed, and the heat dissipation of the permanent heat rod can be met. Moreover, all the permanent heat rods can be arranged in an array in the roadbed through the assembled roadbed module, so that a larger number of permanent heat rods can be set, which is beneficial to provide more cold energy to the foundation; and uniform cooling can be achieved within the roadbed; and the setting of the assembled roadbed module in conjunction with the filling section will not affect the safety of the roadbed construction and operation, and the construction of the assembled roadbed module is convenient and efficient.

[0050] 2. The present invention provides a method for constructing an assembled cooling roadbed structure, wherein the time required for the active layer to completely refreeze is t f The thawing time t required by the construction period d By comparing the above, temporary heat rods can be selected to dissipate heat from the foundation, which can speed up the refreezing rate of the foundation and meet the requirements for stable construction of the underlying structure and superstructure during the construction period. The assembled roadbed module has a high degree of assembly, good construction quality and high construction efficiency. The temporary heat rods can be reused, which greatly reduces the project cost.

[0051] 3. The present invention provides a design method for the construction of an assembled cooling roadbed structure, by calculating the time t required for the active layer to completely refreeze f , and thus can meet the requirements of the construction period for the refrost time t dThe comparison can provide guidance on whether to set up temporary heat rods when constructing the assembled cooling roadbed structure, which is conducive to ensuring the smooth construction of the assembled cooling roadbed structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a cross-sectional schematic diagram of the assembled cooling roadbed structure;

[0053] Figure 2 It is a structural schematic diagram of the assembled roadbed module (the upper side is the bottom);

[0054] Figure 3 It is a schematic diagram of the first structural arrangement of the assembled roadbed module;

[0055] Figure 4 It is a schematic diagram of the second structural cross section of the assembled roadbed module;

[0056] Figure 5 It is a structural schematic diagram of a channel-shaped member;

[0057] Figure 6 It is a plan view schematic diagram of permanent heat rods arranged in a square array;

[0058] Figure 7 A schematic diagram of parameters of temporary heat rods arranged in a square array;

[0059] Figure 8 It is a plan view schematic diagram of permanent heat rods arranged in an equilateral triangle array;

[0060] Fig. 9 Schematic diagram of the parameters of temporary heat rods arranged in an equilateral triangle array.

[0061] Markings in the figure: 1. Assembled roadbed module; 101. Installation hole; 1011. Semicircular notch; 102. Ventilation duct; 11. Bottom plate; 111. Installation groove; 12. Top plate; 13. Side plate; 14. Trough member; 15. Insulation board; 21. Permanent heat rod; 22. Temporary heat rod; 3. Foundation; 4. Cushion layer; 5. Bidirectional geogrid; 6. Pavement structure layer; 7. Slope; 8. Filling section. DETAILED DESCRIPTION

[0062] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0063] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all expressions based on the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0064] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0065] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0066] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0067] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0068] Example 1

[0069] like Figure 1 As shown, an assembled cooling roadbed structure includes a bottom structure, an upper structure and a heat rod array.

[0070] like Figure 6 and Figure 8 As shown, the underlying structure includes a plurality of assembled roadbed modules 1 and a plurality of filling sections 8 , and the upper structure is arranged above the underlying structure, that is, the upper structure is arranged on the assembled roadbed modules 1 and the filling sections 8 .

[0071] The assembled roadbed module 1 is made of one or a combination of reinforced concrete, construction solid waste, industrial solid waste and foamed concrete.

[0072] In this embodiment, the upper structure is provided with a cushion layer 4, a bidirectional geogrid 5 and a pavement structure layer 6 in sequence from bottom to top, and slopes 7 are provided on both lateral sides of the cushion layer 4 and the pavement structure layer 6, that is, the cushion layer 4 is arranged on the assembled roadbed module 1 and the filling section 8.

[0073] like Figure 1 and Figure 6 As shown, the assembled roadbed module 1 is arranged transversely along the roadbed, that is, Figure 1 and Figure 6 The assembled roadbed modules 1 are spaced apart longitudinally along the roadbed, that is, Figure 6 The up and down directions in the roadbed. The bottom of the assembled roadbed module 1 is used to be embedded in the foundation 3 to ensure the lateral and longitudinal positions of the assembled roadbed module 1, thereby ensuring the stability of the structure and the safety of subsequent operations. The filling section 8 is filled between two adjacent assembled roadbed modules 1 in the longitudinal direction of the roadbed; the filling section adopts one or a combination of fill, crushed stone and gravel to better adapt to roadbed deformation. The bottom structure adopts the filling section 8 to fill between two adjacent assembled roadbed modules 1 in the longitudinal direction of the roadbed, so that the bottom structure is complete and the smooth setting of the upper structure is ensured; and the filling section 8 can adapt to the longitudinal deformation of the roadbed, thereby reducing the possibility of lateral dislocation of the assembled roadbed module 1, and ensuring the integrity of the bottom structure during the longitudinal deformation of the roadbed.

[0074] like Figure 2-Figure 4 As shown, a plurality of mounting holes 101 are arranged at intervals at the bottom of the assembled roadbed module 1 along the length direction of the assembled roadbed module 1. The mounting holes 101 are used to set the permanent heat rods 21. The arrangement of the mounting holes matches the arrangement of the permanent heat rods. A ventilation duct 102 is arranged inside the assembled roadbed module 1 along the length direction of the assembled roadbed module 1. The ventilation duct 102 connects all the mounting holes 101 of the assembled roadbed module 1. The ventilation duct 102 includes an air inlet and an air outlet. The air inlet and the air outlet can connect to the outside of the roadbed.

[0075] Wherein, the cross section of the assembled roadbed module 1 is square, rectangular or trapezoidal, etc.;

[0076] And / or, the cross-sectional shape of the ventilation duct 102 is rectangular, circular, elliptical, etc.

[0077] When the cross section of the assembled roadbed module 1 is square and the cross section of the ventilation duct 102 is rectangular, Figure 2 shown.

[0078] In some embodiments, a heat insulation board is provided on the top of the ventilation duct 102 to reduce the ability of the upper structure to directly transfer heat to the foundation and reduce the influence of the heat radiation of the foundation on the heat dissipation of the upper structure. The heat insulation board material can be glass fiber, asbestos, rock wool, silicate, aerogel felt or vacuum board and other thermal insulation materials.

[0079] In one embodiment, Figure 3 As shown, the assembled roadbed module 1 includes a bottom plate 11 and an upper cover, the bottom plate 11 is provided with the mounting holes 101 at intervals along the transverse direction of the roadbed, the bottom plate 11 is provided with mounting grooves 111 on both sides of the longitudinal direction of the roadbed, the mounting grooves 111 are arranged along the transverse direction of the roadbed, and the mounting grooves 111 on both sides are located on both sides of the mounting holes 101, the upper cover includes a top plate 12 and two side plates 13 arranged at intervals along the longitudinal direction of the roadbed, the side plates 13 can be adapted to be inserted into the mounting grooves 111 on the corresponding sides, and the ventilation duct 102 is formed between the bottom plate 11, the top plate 12 and the two side plates 13; the assembled roadbed module 1 is divided into a bottom plate 11 and an upper cover, after the permanent heat rod 21 is constructed, the bottom plate 11 and the upper cover are constructed in sequence, the mounting holes on the bottom plate 11 are convenient for aligning the permanent heat rod 21 for installation, and the side plates of the upper cover are convenient for aligning the mounting grooves 111 on the bottom plate, so that the installation process is simpler and does not affect the function of the assembled roadbed module 1. Furthermore, the heat insulation board 15 can be located on the lower surface, inside or upper surface of the top plate. In this embodiment, the heat insulation board 15 is embedded in the top plate 12 and the two side plates 13 when the assembled roadbed module is prefabricated.

[0080] In another embodiment, if Figure 4 and Figure 5As shown, the assembled roadbed module 1 includes two trough members 14, the openings of the two trough members 14 are arranged opposite to each other, the openings of the trough members 14 are arranged longitudinally along the roadbed, and the bottoms of the two trough members 14 are provided with a plurality of opposite semicircular notches 1011, and the two opposite semicircular notches 1011 are combined to form the mounting hole 101. The assembled roadbed module 1 uses two trough members 14, and first aligns the constructed permanent heat rod 21 through the semicircular notch 1011 of one trough member 14, and then installs another trough member 14 based on the trough member 14, which is more convenient to install and does not affect the function of the assembled roadbed module 1. Furthermore, the heat insulation board 15 is embedded in the trough member 14 when the assembled roadbed module is prefabricated.

[0081] like Figure 1 and Figure 6 As shown, when the transverse width of the roadbed is narrow, an assembled roadbed module 1 can be pulled through and arranged in the transverse direction of the roadbed, such as Figure 1 As shown in the figure, the left and right end faces of the assembled roadbed module 1 are outside the left and right sides of the roadbed, so the passing effect is good, which is conducive to the heat dissipation of the foundation by the heat rod. That is, the air inlet and the air outlet are arranged at the end faces of the assembled roadbed module 1 in the length direction; convection is formed, and the fanning effect is better.

[0082] When the transverse dimension of the roadbed is large, at least two of the assembled roadbed modules 1 are continuously arranged in the transverse direction of the roadbed to facilitate transportation and installation, and the two adjacent assembled roadbed modules 1 in the transverse direction of the roadbed are connected to each other by grouting, which can achieve the sealing of the two adjacent assembled roadbed modules 1 in the transverse direction, making the ventilation duct 102 continuous and the heat dissipation effect better.

[0083] The heat rod array includes a plurality of permanent heat rods 21, which are arranged in the corresponding installation holes 101. The condensation section at the upper part of the permanent heat rod 21 extends into the corresponding ventilation duct 102, and the evaporation section at the lower part of the permanent heat rod 21 is used to extend below the upper limit of the frozen soil in the foundation 3. All the permanent heat rods 21 are arranged in an array in the roadbed through the assembled roadbed module 1.

[0084] like Figure 1 As shown, the lateral distance between the permanent heat rods 21 installed on both sides of the roadbed and the foot of the slope 7 on the corresponding side is not less than 0.5m.

[0085] The assembled cooling roadbed structure described in this embodiment can discharge all the heat displaced from the frozen soil in the foundation 3 by the permanent heat rods 21 through the ventilation ducts 102 of the corresponding assembled roadbed modules 1, so that the permanent heat rods 21 can be set below the transverse middle part of the roadbed, and the heat dissipation of the permanent heat rods 21 can be met. In addition, all the permanent heat rods 21 can be arranged in an array in the roadbed through the assembled roadbed module 1, so that a larger number of permanent heat rods 21 can be set, which is beneficial to provide more cold energy to the foundation, and are evenly distributed in the roadbed, and can achieve uniform cooling within the roadbed range; and the setting of the assembled roadbed module 1 will not affect the safety of roadbed construction and operation, and the construction of the assembled roadbed module 1 is convenient and efficient.

[0086] Example 2

[0087] A method for constructing an assembled cooling roadbed structure, used for constructing the assembled cooling roadbed structure described in Example 1, comprises the following steps:

[0088] S01. Level the site and mark the locations of all heating rods at the construction site; when the active layer is completely frozen back, the time required is t f The refrost time t is greater than the construction period requirement d The heat rods include a number of permanent heat rods 21 and a number of temporary heat rods 22; when the active layer is completely thawed, the time required is t f Less than or equal to the refrost time required by the construction period t d When, the heat rod includes a plurality of permanent heat rods 21;

[0089] S02. Install all the heat rods at the marked positions so that the evaporation ends of the heat rods are inserted below the upper limit of the frozen soil in the natural foundation;

[0090] S03, the time required for the active layer to completely freeze back f The refrost time t is greater than the construction period requirement d At t d After that, the temporary heat rod 22 added during the construction period is removed, and the heat rod hole of the temporary heat rod 22 is backfilled, and then the assembled roadbed module 1 is installed; when the active layer is completely thawed, the time t f Less than or equal to the refrost time required by the construction period t d At t f Then install the assembled roadbed module 1;

[0091] The assembled roadbed modules are prefabricated and produced according to the size, shape, permanent heat rod arrangement form and quantity. When at least two assembled roadbed modules 1 are used in the transverse direction of the roadbed, two adjacent assembled roadbed modules 1 are connected in the transverse direction by grouting or the like.

[0092] S04, constructing a filling section; for example, filling between two identical assembled roadbed modules 1 in the longitudinal direction of the roadbed with crushed stone and gravel.

[0093] S05. Construct superstructure.

[0094] In step S05, constructing the superstructure includes sequentially constructing the cushion layer 4, laying the bidirectional geogrid 5 and constructing the pavement structure layer 6. When constructing the cushion layer 4 and the pavement structure layer 6, the side slopes 7 on both sides are constructed simultaneously.

[0095] The existing heat rod design does not take into account the complete defrosting period of the foundation, and only calculates the number of heat rods according to the defrosting period required during the construction period. This will result in some foundation heat not being released completely and being stored until the operation period, that is, the construction period and the operation period are not considered together, which has an adverse impact on highway operation. Therefore, it is necessary to combine the two stages to achieve the energy balance of the entire process of roadbed construction and operation. The assembled cooling roadbed structure construction method described in this embodiment takes the time t required for the active layer to completely defrost through f The thawing time t required by the construction period d By comparing the temporary heat rod 22, the foundation can be cooled, which can accelerate the refrost of the foundation and meet the requirements of stable construction of the bottom structure and the upper structure during the construction period. The time required for the active layer to completely refrost is t f It is related to the operation period, that is, the method takes into account the complete thawing period of the foundation and the amount of cold required for the complete thawing of the foundation, so that the method simultaneously takes into account the energy balance of the entire process of the construction period and the operation period, and achieves the energy balance of the entire construction and operation process. The assembled roadbed module 1 has a high degree of assembly, good construction quality, and high construction efficiency, that is, on the basis of controlling the melting of frozen soil with heat rods, combined with the intelligent roadbed construction technology, high-quality and rapid construction of the roadbed is achieved; the temporary heat rods are reusable, which greatly reduces the project cost.

[0096] Example 3

[0097] The present invention provides a design method for the construction of an assembled cooling roadbed structure, which is used to guide the construction method of the assembled cooling roadbed structure, and comprises the following steps:

[0098] S1: Calculate the annual heat transfer Q of the permanent heat rod 21 under design conditions using the energy balance method 2 and the arrangement spacing s of the permanent heat rod 21 s ; and calculate the cold energy required to completely refrozen the active layer of the natural foundation 3 Q 1 ;

[0099] In step S1, the annual heat transfer Q of the permanent heat rod 21 is 2 It is related to the model of the permanent heat rod 21. For details, please refer to the relevant specifications for calculation. The arrangement spacing s of the permanent heat rod 21 s Please refer to the relevant specifications.

[0100] In step S1, the cooling energy required to completely refrozen the active layer of the natural foundation 3 is Q 1 The calculation formula is:

[0101]

[0102] Where: n is the number of parts into which the active layer is divided, n≥1; i is the index; H i is the thickness of the i-th layer; W is the width between the slope toes on both sides of the embankment; ρ di is the dry density of the i-th layer; C i is the specific heat capacity of the i-th layer; T avgi is the average ground temperature of the i-th layer; T pci is the phase transition temperature of the i-th layer of soil; ω i is the water content of the i-th layer; ω iu is the unmoved water content of the i-th layer; L is the latent heat of crystallization of water or melting of ice. It is preferred that the active layer is divided into n layers by geological stratification.

[0103] The cold energy required by the above natural foundation 3 active layer to completely refrozen Q 1 The calculation formula for the cooling energy demand Q 1 The calculation is performed with high accuracy and small amount of calculation.

[0104] S2: Based on the annual heat transfer Q of the permanent heat rod 21 2 , the arrangement spacing s of the permanent heat rods 21 s and the cooling energy demand Q for complete refrigeration of the active layer 3 of the natural foundation 1 Calculate the time t required for the active layer to completely refrozen f , the time required for the active layer to completely freeze back to its original state is t f The calculation formula is:

[0105]

[0106] S3: Determine the time t required for the active layer to completely refreeze f Is it greater than the refrost time t required during the construction period? d If so, determine the number m of temporary hot bars 22 and the center spacing s of adjacent temporary hot bars 22 to be added on the cross section of the roadbed during the construction period, and according to the permanent hot bar 21 spacing s s , the number m of temporary hot bars 22 on the roadbed cross section and the center spacing s of adjacent temporary hot bars 22 guide the construction of permanent hot bars 21 and temporary hot bars 22; if not, according to the spacing s of permanent hot bars 21 s Guide the construction of permanent heat rod 21. Among them, the refrigeration time t required by the construction period d Related to geographical location and stratum.

[0107] In step S3, the effective radius s of the temporary heating rod 22 during the construction period is first calculated. s ', effective radius of temporary hot rod 22 during construction period s s The calculation formula of ' is:

[0108]

[0109] Where: Δt is the working time of the temporary heating rod 22 in one year; t is the time variable; T s is the annual average ground temperature; T a is the annual average temperature; 0 is the outer diameter of the temporary hot rod 22; R a is the thermal resistance of the temporary heat rod 22; f is the thermal conductivity of the fins of the temporary heat rod 22; L e is the length of the evaporation section of the temporary heat rod 22;

[0110] Then according to the effective radius s of the temporary hot rod 22 s 'Calculate the number m of temporary hot rods 22 on the roadbed cross section. The calculation formula for the number m of temporary hot rods 22 on the roadbed cross section is:

[0111]

[0112] Where: W is the width between the slope toes on both sides of the roadbed;

[0113] And according to the temporary hot rod 22 effective radius s s ' and the arrangement of the newly added temporary heat rods 22 to calculate the center distance s of adjacent temporary heat rods 22;

[0114] Among them, when the arrangement of the newly added temporary hot rod 22 is a square, as Figure 7 As shown, s = S s ' / 1.128; When the arrangement of the newly added temporary heat rod 22 is an equilateral triangle, such as Fig. 9 As shown, s = S s ' / 1.05.

[0115] The above calculation method can quickly and accurately calculate the number m of temporary heat rods 22 on the roadbed cross section that need to be added during the construction period and the center distance s of adjacent temporary heat rods 22, which is convenient for guiding the layout of temporary heat rods 22.

[0116] This embodiment provides a design method for the construction of the assembled cooling roadbed structure, which can calculate the time t required for the active layer to completely refreeze. f , and thus can meet the requirements of the construction period for the refrost time t d The comparison is carried out to provide guidance on whether to set up a temporary heat rod 22 when constructing the assembled cooling roadbed structure, which is beneficial to ensuring the smooth construction of the assembled cooling roadbed structure.

[0117] In the present invention, before the construction of the assembled cooling roadbed structure, the energy balance of the entire construction and operation process is considered, and the time required for the active layer to completely refreeze t f Based on the above, temporary heat rods 22 are selectively set to achieve complete refreezing of the foundation before construction, reserve cold energy in advance to balance the thermal disturbance during construction and operation, and reduce the impact on highway operation.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An assembled cooling roadbed structure, characterized in that: include: A bottom layer structure, the bottom layer structure comprising a plurality of assembled roadbed modules (1) and a plurality of filling sections (8), the assembled roadbed modules (1) being arranged transversely along the roadbed, the assembled roadbed modules (1) being spaced apart longitudinally along the roadbed, the bottom of the assembled roadbed module (1) being used to be embedded in the foundation (3), and the filling section (8) being filled between two adjacent assembled roadbed modules (1) in the longitudinal direction of the roadbed; a plurality of mounting holes (101) being spaced apart at the bottom of the assembled roadbed module (1) along the length direction of the assembled roadbed module (1), a ventilation duct (102) being arranged inside the assembled roadbed module (1) along the length direction of the assembled roadbed module (1), the ventilation duct (102) being connected to all the mounting holes (101) of the assembled roadbed module (1), the ventilation duct (102) comprising an air inlet and an air outlet, the air inlet and the air outlet being able to be connected to the outside of the roadbed; An upper structure, the upper structure being arranged above the lower structure; A heat rod array, the heat rod array comprising a plurality of permanent heat rods (21), the permanent heat rods (21) being arranged in corresponding mounting holes (101), the condensation section at the upper portion of the permanent heat rods (21) extending into the corresponding ventilation duct (102), the evaporation section at the lower portion of the permanent heat rods (21) being used to extend below the upper limit of frozen soil in the foundation (3), and all the permanent heat rods (21) being arranged in an array in the roadbed through the assembled roadbed module (1).

2. The assembled cooling roadbed structure according to claim 1 is characterized in that: The cross section of the assembled roadbed module (1) is square, rectangular or trapezoidal; And / or, the cross-sectional shape of the ventilation duct (102) is rectangular, circular or elliptical.

3. The assembled cooling roadbed structure according to claim 2 is characterized in that: The assembled roadbed module (1) comprises a bottom plate (11) and an upper cover, wherein the bottom plate (11) is provided with the mounting holes (101) at intervals along the transverse direction of the roadbed, and the bottom plate (11) is provided with mounting grooves (111) on both sides of the longitudinal direction of the roadbed, wherein the mounting grooves (111) are arranged along the transverse direction of the roadbed, and the mounting grooves (111) on both sides are located on both sides of the mounting holes (101), and the upper cover comprises a top plate (12) and two side plates (13) arranged at intervals along the longitudinal direction of the roadbed, wherein the side plates (13) can be adapted to be inserted into the mounting grooves (111) on the corresponding sides, and the ventilation duct (102) is formed between the bottom plate (11), the top plate (12) and the two side plates (13); Alternatively, the assembled roadbed module (1) comprises two trough members (14), the openings of the two trough members (14) are arranged opposite to each other, the openings of the trough members (14) are arranged along the longitudinal direction of the roadbed, a plurality of opposite semicircular notches (1011) are arranged at the bottom of the two trough members (14), and the two opposite semicircular notches (1011) are combined to form the mounting hole (101).

4. The assembled cooling roadbed structure according to claim 1 is characterized in that: A heat insulation board (15) is provided on the top of the ventilation duct (102).

5. The assembled cooling roadbed structure according to claim 1 is characterized in that: At least two of the assembled roadbed modules (1) are arranged continuously in the transverse direction of the roadbed, and two adjacent assembled roadbed modules (1) in the transverse direction of the roadbed are connected to each other by grouting.

6. The assembled cooling roadbed structure according to claim 1 is characterized in that: The air inlet and the air outlet are arranged at both end faces of the assembled roadbed module (1) in the length direction; And / or, the upper structure is provided with a cushion layer (4), a bidirectional geogrid (5) and a pavement structure layer (6) in sequence from bottom to top, the cushion layer (4) and the pavement structure layer (6) are provided with side slopes (7) on both lateral sides, and the lateral spacing between the permanent heat rods (21) installed on both lateral sides of the roadbed and the foot of the side slope (7) on the corresponding side is not less than 0.5 m; And / or, the assembled roadbed module (1) is made of one or a combination of reinforced concrete, construction solid waste, industrial solid waste and foamed concrete; And / or, the filling section (8) is made of one or a combination of soil, crushed stone and gravel.

7. A method for constructing an assembled cooling roadbed structure, characterized in that: The method for constructing the assembled cooling roadbed structure as claimed in any one of claims 1 to 6 comprises the following steps: S01. Level the site and mark the locations of all heating rods at the construction site; when the active layer is completely frozen back, the time required is t f The refrost time t is greater than the construction period requirement d The heat rods include a number of permanent heat rods (21) and a number of temporary heat rods (22); when the active layer is completely refrozen, the time t f Less than or equal to the refrost time required by the construction period t d When the heat rod comprises a plurality of permanent heat rods (21); S02. Install all the heat rods at the marked positions so that the evaporation ends of the heat rods are inserted below the upper limit of the frozen soil in the natural foundation; S03, the time required for the active layer to completely freeze back f The refrost time t is greater than the construction period requirement d At t d After that, the temporary heating rod (22) added during the construction period is removed, and the heating rod hole of the temporary heating rod (22) is backfilled, and then the assembled roadbed module (1) is installed; when the time required for the active layer to completely thaw is t f Less than or equal to the refrost time required by the construction period t d At t f Then installing the assembled roadbed module (1); S04, construction filling section (8); S05. Construct superstructure.

8. A design method for the construction of an assembled cooling roadbed structure, characterized in that: The method for guiding the construction of the assembled cooling roadbed structure as claimed in claim 7 comprises the following steps: S1: Calculate the annual heat transfer Q2 of the permanent heat rod (21) and the arrangement spacing s of the permanent heat rod (21) under design conditions using the energy balance method s ; and calculate the cooling energy required to completely refrozen the active layer of the natural foundation (3) Q1; S2: Based on the annual heat transfer Q2 of the permanent heat rod (21) and the arrangement spacing s of the permanent heat rod (21) s and natural foundation (3) The cooling energy demand Q1 for the complete thawing of the active layer is calculated as the time t required for the complete thawing of the active layer f , the time required for the active layer to completely freeze back to its original state is t f The calculation formula is: S3: Determine the time t required for the active layer to completely refreeze f Is it greater than the refrost time t required during the construction period? d If so, determine the number m of temporary hot bars (22) on the roadbed cross section to be added during the construction period and the center spacing s of adjacent temporary hot bars (22), and according to the spacing s of the permanent hot bars (21) s , the number m of temporary heating rods (22) on the cross section of the roadbed and the center spacing s of adjacent temporary heating rods (22) guide the construction of permanent heating rods (21) and temporary heating rods (22); if not, according to the spacing s of permanent heating rods (21) s Guide for constructing permanent heat rod (21).

9. The design method for the construction of an assembled cooling roadbed structure according to claim 8, characterized in that: In step S1, the calculation formula for the cold energy demand Q1 for completely refreezing the active layer of the natural foundation (3) is: Where: n is the number of parts into which the active layer is divided, n≥1; i is the index; H i is the thickness of the i-th layer; W is the width between the slope toes on both sides of the embankment; ρ di is the dry density of the i-th layer; C i is the specific heat capacity of the i-th layer; T avgi is the average ground temperature of the i-th layer; T pci is the phase transition temperature of the i-th layer of soil; ω i is the water content of the i-th layer; ω iu is the unmoved water content of the i-th layer; L is the latent heat of crystallization of water or melting of ice.

10. The design method for the construction of an assembled cooling roadbed structure according to claim 8, characterized in that: In step S3, the effective radius s of the temporary heating rod (22) during the construction period is first calculated. s ', effective radius s of temporary heating rod (22) during construction period s The calculation formula of ' is: Where: Δt is the working time of the temporary heat rod (22) in one year; t is the time variable; T s is the annual average ground temperature; T a is the annual average temperature; d0 is the outer diameter of the temporary heating rod (22); R a is the thermal resistance of the temporary heat rod (22); f L is the thermal conductivity of the fins of the temporary heat rod (22); e is the length of the evaporation section of the temporary hot rod (22); Then according to the effective radius s of the temporary hot rod (22) s 'Calculate the number m of temporary hot rods (22) on the roadbed cross section. The calculation formula for the number m of temporary hot rods (22) on the roadbed cross section is: Where: W is the width between the slope toes on both sides of the roadbed; And according to the effective radius s of the temporary hot rod (22) s ' and the arrangement of the newly added temporary heat rods (22) to calculate the center distance s between adjacent temporary heat rods (22); When the newly added temporary heat rod (22) is arranged in a square, s=s s ' / 1.128; when the arrangement of the newly added temporary heat rod (22) is an equilateral triangle, s=s s ' / 1.05.

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