Filling construction method for highway subgrade in desert area
By adopting the filling construction method of the wind-accumulated sand dry pressing method in desert areas, the problems of scarcity of materials and water resources in highway subgrade construction in desert areas have been solved, and efficient, economical and sustainable highway subgrade construction has been achieved.
Patent Information
- Application Number
- CN202411757574.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-02-28
AI Technical Summary
Highway subgrade filling construction in desert areas faces the problems of scarce materials, ultra-long-distance transportation, high construction costs and lack of water resources. Conventional construction technology is difficult to meet the requirements of economic and efficiency.
The filling construction methods of roadbeds in desert areas are adopted, including measuring and laying lines, clearing tables, building construction walkways, wrapping red soil sand, filling wind-absorbing sand, leveling and rolling and filling top-sealing layers. Through the construction process of dry pressure of the air-catalyst sand, sand is taken on-site and waste is turned into treasure, solving the problems of scarcity of materials and water resources.
It has achieved efficient, economic and sustainable development of roadbeds in desert areas, reduced construction costs, avoided the problem of water resource shortage, and improved construction efficiency and stability of roadbeds.
Smart Images
Figure CN119531205A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of roadbed construction, and in particular relates to a filling construction method for a highway roadbed in a desert area. Background Art
[0002] In the construction of modern transportation infrastructure, the roadbed, as a key supporting part of the track or road surface, bears the important task of building a solid foundation for the laying of the upper track or road surface. While bearing various static and dynamic loads, it transfers and diffuses these loads to the deep foundation, thereby ensuring the safe and smooth operation of trains or vehicles.
[0003] However, the special geographical environment of desert areas has brought severe challenges to the construction of highway subgrade. Desert areas have extremely significant characteristics. Their climate is dry, the annual precipitation is extremely low, and the sparse and short vegetation cover not only cannot effectively stabilize the surface, but also makes it difficult to provide the auxiliary materials required for construction. At the same time, the vast desert surface has complex and changeable morphology, undulating sand dunes, and loose sand, which makes engineering operations face many difficulties. The most prominent is that engineering materials are extremely scarce. If conventional construction technology is used for highway subgrade filling, a large amount of road construction materials have to be transported from remote areas to the construction site over long distances, which increases the difficulty of construction, prolongs the construction period, and greatly increases the cost of road construction. It will also have a great impact on the normal operation and efficiency of mechanical equipment. In summary, when carrying out highway subgrade filling construction in desert areas, conventional construction technology can no longer meet the requirements of economy and efficiency. Summary of the invention
[0004] In view of the shortcomings existing in the related art, the purpose of the present invention is to provide a filling construction method for a highway roadbed in a desert area, so as to overcome the existing difficulties and achieve efficient, economical and sustainable development of desert highway construction.
[0005] To achieve the above object, the present invention provides the following technical solutions:
[0006] A filling construction method for a highway subgrade in a desert area comprises:
[0007] S1. Surveying and setting out: Determine the location, shape and size of the roadbed in desert areas;
[0008] S2, surface clearing: clearing the surface vegetation, humus, garbage and sand layers that do not meet the requirements of roadbed filling within the scope of highway roadbed construction. The surface clearing width is greater than the designed road surface width;
[0009] S3. Construction of construction access roads: Use red soil and gravel to build construction access roads. The built construction access roads are close to the edge of the highway subgrade and are constructed together with the wind erosion prevention edging. Set up car-passing platforms at set intervals on the construction access roads;
[0010] S4. Red soil gravel edging: The anti-wind erosion red soil gravel edging is transported by dump trucks and flattened by bulldozers and graders. The wind erosion red soil gravel edging is leveled and rolled together with the subsequent backfill of aeolian sand;
[0011] S5. Filling of aeolian sand: The aeolian sand backfill adopts the method of stationing platforms outside the slope. A platform is built at a set distance beside the roadbed. The bulldozer pushes the aeolian sand to the front of the platform, and then the loader transports it to the roadbed and fills and compacts it in layers.
[0012] S6. Leveling and rolling: Use a roller to roll the road according to the steps of stabilizing pressure, leveling, initial rolling, repeated rolling and final rolling. Roll the road first at the edge and then in the middle, first fast and then slow. Control the number of rolling passes to 1-2 times and the total number of rolling passes to 8-10 times.
[0013] S7. Fill and seal the top layer: Use red soil and gravel to seal the top layer.
[0014] In some embodiments, step S1 specifically includes:
[0015] S11. Construction preparation: obtain topographic maps, geological survey reports and highway engineering design documents of desert areas, and calibrate measuring instruments;
[0016] S12, control point re-survey and encryption: re-survey the control points provided in the highway engineering design documents, compare the measured data with the original data, and encrypt the original control points based on the shape, length, width and terrain characteristics of the highway subgrade. The encrypted points are evenly distributed along the highway route, and GPS-RTK technology is used for plane and elevation control measurement;
[0017] S13, centerline stakeout: According to the coordinates and direction of the centerline of the highway in the highway engineering design documents, use GPS-RTK technology to determine the starting point, end point and turning point of the centerline of the roadbed on the spot. After confirming that the accuracy of the centerline points meets the quality standards, set up wooden or concrete stakes and mark the numbers and mileage stakes;
[0018] S14. Stake setting out of roadbed side piles: Calculate the side pile positions based on the designed roadbed width, side slope gradient and centerline pile elevation, and use GPS-RTK technology to stake out the side pile positions. After the side pile positions are determined, set up obvious signs and marks, and regularly review and adjust the side pile positions.
[0019] S15. Leveling and elevation control: Set leveling points within the construction scope to form a closed or attached leveling route, use a level to measure the elevation difference according to the set leveling accuracy requirements, record the elevation data, control the elevation of each part of the roadbed according to the leveling points, and set elevation marks on the side piles or center line piles.
[0020] In some embodiments, step S2 specifically includes:
[0021] S21. Vegetation cleaning: uproot or remove plants within the scope of highway roadbed construction, and clean up humus soil;
[0022] S22, sand layer cleaning: remove the sand layer that is too loose and contains a lot of salt on the surface, and clean it to a set depth so that the remaining sand layer can provide sufficient bearing capacity for the highway subgrade;
[0023] S23. Garbage and obstacle removal: clearing garbage and obstacles that affect construction in the construction area;
[0024] S24. Site leveling: Flatten the cleaned site surface to meet the basic shape requirements for roadbed filling.
[0025] In some of the embodiments, in step S5, a platform is built on the roadbed every 30-50 m, and the thickness of each layer of compacted aeolian sand is controlled to be 30-50 cm.
[0026] In some embodiments, in step S5, the virtual spreading coefficient of the aeolian sand is between 1.2 and 1.3, and the maximum dry density of the aeolian sand is 1.71 g / cm 3 The thickness of the aeolian sand in the bottom layer should be relatively large and controlled at nearly 50cm.
[0027] In some of the embodiments, in step S2, the surface clearing width is twice the designed road surface width.
[0028] In some of the embodiments, in step S3, the constructed construction access road is 3.5 m wide and 20-30 cm thick, and a vehicle staging platform is provided every 200 m on the construction access road.
[0029] In some of the embodiments, in step S6, adjacent rolling wheel tracks overlap by 0.2-0.3 m.
[0030] In some of the embodiments, in step S6, the roller is a Caterpillar CS76 XT self-propelled vibratory roller, which can independently walk and work on the formed sand base surface.
[0031] In some of the embodiments, in step S5, in the excavation section of high sand dunes, a high-power bulldozer is selected to push away the aeolian sand in the downwind direction and roughly level it.
[0032] Compared with the prior art, the present invention has the following beneficial effects:
[0033] 1. The method for constructing the roadbed in desert areas provided by the present invention adopts the construction technology of aeolian sand dry pressing method, which takes sand on site and turns waste into treasure, solves the problem of long-distance transportation of backfill materials in desert areas and increases construction costs, and also overcomes the difficulties of water resource scarcity and shortage of engineering water.
[0034] 2. The air in desert areas is dry and precipitation is scarce. The natural moisture content within 1m of the surface layer of aeolian sand is about 0.1%. After paving, leveling and rolling, its moisture content is infinitely close to 0. The filling construction method for highway roadbed in desert areas provided by the present invention is suitable for use in dry desert environments and has good safety. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0036] Figure 1 A schematic diagram of a filling structure of an embodiment of a filling construction method for a highway subgrade in a desert area of the present invention;
[0037] Figure 2 The present invention is a flowchart of an embodiment of a method for filling and constructing a highway subgrade in a desert area.
[0038] In the figure:
[0039] 1. Ground line; 2. Wind-blown sand; 3. Center line of roadbed; 4. Red soil and gravel edging; 5. Earthwork capping; 6. Hard shoulder; 7. Structural layer; 8. Asphalt concrete. DETAILED DESCRIPTION
[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0041] In the description of the present invention, it should be understood that the terms "center", "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.
[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0043] See attached Figure 1 to Figure 2 , a schematic embodiment of the filling construction method of the highway roadbed in the desert area proposed by the present invention is given, and the filling construction method of the highway roadbed in the desert area includes the following steps:
[0044] S1. Surveying and setting out: Determine the location, shape and size of the roadbed in desert areas;
[0045] S2, surface clearing: clearing the surface vegetation, humus, garbage and sand layers that do not meet the requirements of roadbed filling within the scope of highway roadbed construction. The surface clearing width is greater than the designed road surface width;
[0046] S3. Construction of construction access roads: Use red soil and gravel to build construction access roads. The built construction access roads are close to the edge of the highway subgrade and are constructed together with the wind erosion prevention edging. Set up car-passing platforms at set intervals on the construction access roads;
[0047] S4, red soil gravel edging 4: The anti-wind erosion red soil gravel edging 4 is transported by dump trucks and flattened by bulldozers and graders. The wind erosion red soil gravel edging 4 is flattened and rolled together with the subsequent backfill of aeolian sand 2;
[0048] S5. Filling of aeolian sand 2: The aeolian sand 2 is backfilled by the side slope external platform method. A platform is built at a set distance beside the roadbed. The bulldozer pushes the aeolian sand 2 to the front of the platform, and then the loader transports it to the roadbed, and fills and compacts it in layers.
[0049] S6. Leveling and rolling: Use a roller to roll the road according to the steps of stabilizing pressure, leveling, initial rolling, repeated rolling and final rolling. Roll the road first at the edge and then in the middle, first fast and then slow. Control the number of rolling passes to 1-2 times and the total number of rolling passes to 8-10 times.
[0050] S7. Fill and seal the top layer: Use red soil and gravel to seal the top layer.
[0051] Aeolian sand 2 is a sand layer that is blown up by the wind and then precipitated, and the particles are fine and uniform. It has the characteristics of low natural moisture content, poor water retention, poor plasticity and shear resistance, non-collapse, uniform settlement, easy compaction, etc. In the actual construction process, a standard compaction experiment can be carried out on the aeolian sand 2 of the construction section in advance. In the present embodiment, it can be concluded according to the experimental data that the compaction law of aeolian sand 2 is that as the water content increases, the compacted dry density first decreases and then increases (in a concave curve), and two peaks appear, and the maximum dry density appears at a water content close to zero or close to saturation. This is because aeolian sand is very loose when it is in a dry state, and the bonding force is almost close to zero. At this time, it is mainly the internal friction that needs to be overcome. Under the action of external forces such as rolling and vibration, the aeolian sand particles will move toward the gap direction, thereby filling and inlaying each other, and squeezing and compacting.
[0052] In this embodiment, step S1 specifically includes:
[0053] S11. Construction preparation: obtain topographic maps, geological survey reports and highway engineering design documents of the desert area, and calibrate measuring instruments; topographic maps are used to understand the surface morphology of the desert area, geological survey reports provide information on underground sand layers, and highway engineering design documents specify indicators such as the grade, route, roadbed width, and slope gradient of the highway. Calibrated measuring instruments include total stations, levels, GPS receivers, etc. In addition, auxiliary tools such as benchmarks, prisms, and steel rulers must be prepared.
[0054] S12. Resurvey and encryption of control points: Resurvey the control points provided in the highway engineering design documents, compare the measured data with the original data, and encrypt the original control points based on the shape, length, width and terrain characteristics of the highway subgrade. The encrypted points are evenly distributed along the highway route, and GPS-RTK technology is used for plane and elevation control measurements. The control points to be resurveyed include guide points, leveling points, etc. Since wind and sand erosion and landform changes in desert areas may cause control points to be displaced or damaged, high-precision total stations and levels are used to measure the distance, angle and height difference between control points, and compare the measured data with the original data. If the deviation exceeds the range, the cause must be identified and corrected, and the damaged control points must be restored or replaced.
[0055] S13, centerline stakeout: According to the coordinates and direction of the centerline of the highway in the highway engineering design documents, the starting point, end point and turning point of the centerline 3 of the roadbed are determined on the spot using GPS-RTK technology. After confirming that the accuracy of the centerline points meets the quality standards, wooden or concrete piles are set up and marked with numbers and mileage pile numbers; considering factors such as sand dune obstruction in desert areas that affect satellite signal reception, methods such as rear intersection or front intersection of the total station are flexibly adopted. Mileage piles are set up at a certain interval (20m-50m for straight sections and 10m-20m for curved sections) along the centerline 3 of the roadbed to accurately mark the length and position of the centerline 3 of the roadbed, providing a basis for the width of the roadbed filling and the construction of the slope. Due to the effect of wind and sand, the mileage piles need to be buried deeper, and sandbags or protective casings are used around them to ensure stability and visibility.
[0056] S14. Stake setting out of roadbed: Calculate the position of the side piles according to the designed roadbed width, slope gradient and centerline pile elevation, and use GPS-RTK technology to set out the position of the side piles. After the position of the side piles is determined, set up obvious signs and marks, and regularly review and adjust the position of the side piles. Considering the erosion of wind and sand flow and the movement of sand dunes in desert areas, a certain width should be reserved when calculating the position of the side piles to ensure the stability of the slope and the installation of protective facilities. After the wind and sand or after the roadbed is filled to a certain height, check whether the side piles are displaced and correct them.
[0057] S15. Leveling and elevation control: Set leveling points within the construction scope to form a closed or attached leveling route, use a level to measure the height difference according to the set leveling accuracy requirements, record the elevation data, control the elevation of each part of the roadbed according to the leveling points, and set elevation marks on the side piles or center line piles. Leveling points should be selected in places with high terrain that are not easily flooded or buried by wind and sand, such as the top of a sand dune or on a sand hill, with a spacing of no more than 2km.
[0058] In this embodiment, step S2 specifically includes:
[0059] S21. Vegetation cleaning: Uproot or remove plants within the scope of highway roadbed construction, and clean up humus soil; although the vegetation in desert areas is sparse and short, it still needs to be cleaned up. You can choose to use manual or mechanical (such as small bulldozers) to uproot or remove plants. For some desert plants with deep roots, ensure that all their roots are removed to prevent the plants from continuing to grow after the roadbed is filled and destroying the roadbed structure.
[0060] S22. Sand layer cleaning: Remove the sand layer that is too loose and contains a lot of salt. Clean to a set depth so that the remaining sand layer can provide sufficient bearing capacity for the highway subgrade; use a loader or excavator to dig out and transport away the sand layer that does not meet the filling requirements.
[0061] S23. Garbage and obstacle removal: Clean up garbage and obstacles that may affect construction in the construction area; garbage such as discarded plastics, metals and other waste, and obstacles that may affect construction, such as large rocks, etc. These garbage and obstacles will affect the quality of the roadbed and the smooth progress of construction, so they must be removed thoroughly.
[0062] S24. Site leveling: Flatten the cleaned site surface to meet the basic shape requirements of the roadbed filling. You can choose to use a grader to flatten the cleaned site surface to make the site meet the basic shape requirements of the roadbed filling, and create good conditions for subsequent compaction and other work. During the leveling process, pay attention to controlling the flatness and slope of the site. The flatness error is within the range of ±3cm, and the slope meets the design drainage requirements.
[0063] In this embodiment, in step S5, a platform is built at every 30-50m beside the roadbed to better fill the aeolian sand 2 and improve work efficiency. The thickness of each layer of the aeolian sand 2 filled and compacted in layers is controlled to be 30-50cm. This thickness range can effectively control the construction time of each layer while ensuring the compaction quality, and the sand layer within this range can achieve a better compaction effect under the action of the compaction equipment, which is conducive to the effective transfer of compaction energy to each particle inside the sand layer.
[0064] In this embodiment, in step S5, the virtual spreading coefficient of the aeolian sand 2 is between 1.2 and 1.3, and the maximum dry density of the aeolian sand 2 is 1.71 g / cm 3 The virtual thickness of the bottom layer of aeolian sand 2 should be relatively large, and controlled at nearly 50 cm. The virtual thickness of the bottom layer of aeolian sand 2 is relatively large, which can better adapt to the stress of the roadbed after compaction and maintain the stability of the aeolian sand itself.
[0065] In order to facilitate the construction of the construction access road and prevent excessive wind and sand from burying the roadbed, in this embodiment, in step S2, the surface clearing width is twice the designed width of the road surface. When the designed width of the road surface of a certain project is 10m, the surface clearing width is 20m. In step S3, the construction access road is built with a width of 3.5m and a thickness of 20-30cm, and a car pass is set every 200m on the construction access road.
[0066] In step S6, in order to prevent under-pressure and missed pressure, in this embodiment, adjacent rolling wheel tracks overlap by 0.2-0.3m.
[0067] When selecting compaction equipment, the compaction machinery must meet two basic conditions: one is to have sufficient exciting force, and the other is to be able to walk and work independently on the formed sand base surface. In this embodiment, in step S6, the roller selects a Caterpillar CS76 XT self-propelled vibratory roller to walk and work independently on the formed sand base surface.
[0068] In order to better prevent wind and fix sand, in this embodiment, in step S5, in the high sand dune excavation section, a high-power bulldozer is selected to push and discard the wind-blown sand 2 along the downwind direction and roughly level it. After the surface is cleared in step S2, measures such as dune protection fences are taken as soon as possible to prevent the dunes from moving and bury the roadbed.
[0069] In actual construction, the amount of water evaporation between some sand dunes is large, so soft salt crust and salt frost will be formed. Before construction, this kind of saline soil foundation should be tested for soil salt properties and salt content. If the test fails, it should be replaced with suitable fillers.
[0070] In this embodiment, the wind-blown sand anti-erosion treatment step is also included: after the wind-blown sand roadbed is backfilled, the slope is unstable and prone to wind erosion, and the bottom of the slope is easily hollowed out, resulting in slope collapse and local settlement. Therefore, red soil gravel edging treatment is used to solve the above problems. The thickness of the wind-blown sand edging is closely related to the backfill height of the wind-blown sand roadbed. The greater the backfill height of the wind-blown sand, the easier it is for the slope to become unstable, and the shoulder collapse phenomenon is more likely to occur, and the width of the red soil gravel edging is required to be larger.
[0071] See attached Figure 1 , which is a schematic diagram of the filling structure of an embodiment of the filling construction method of the highway roadbed in the desert area. The maximum backfill thickness of the roadbed in this area is 2.4m. The wind-blown sand 2 is backfilled in layers on the ground line 1 after the surface is cleared, and each layer is 30-50cm thick. The red soil gravel edging 4 is also layered, with an outer slope of 1:5 and a natural slope on the inner side. The width of the top surface of each layer is 0.75-1m. Then the sealing top layer is filled to form the earthwork capping 5, where red soil gravel is used with a thickness of 40cm. A structural layer 7 is provided on the earthwork capping 5, and the structural layer 7 is a structural layer 7 of 20cm red soil gravel mixed with 25% crushed stone. Asphalt concrete 8 can be paved above the structural layer 7, and the thickness of the asphalt concrete 8 is 5cm. Hard shoulders 6 can be provided on both sides of the asphalt concrete 8, wherein the transverse slope of the asphalt concrete 8 along the center line 3 of the roadbed to both sides is 3%, and the transverse slope of the hard shoulders 6 on both sides is 4%. When it rains or water accumulates on the road, water will flow from the higher side of the road to the lower side under the effect of the transverse slope, which can effectively prevent water accumulation on the road. The 3% transverse slope can ensure that rainwater is quickly drained away from the roadway formed by the asphalt concrete 8, maintaining the dryness of the road surface and safe driving conditions. In addition to its own drainage task, the hard shoulder 6 also receives part of the accumulated water discharged from the asphalt concrete 8 road surface. The larger 4% transverse slope can enable the hard shoulder 6 to quickly drain the accumulated water away from the highway range, preventing the accumulated water from accumulating on the hard shoulder 6 and the edge of the roadway. In addition, the hard shoulder 6 is usually used as an emergency parking strip. Ensuring its good drainage performance can prevent vehicles from falling into accumulated water during emergency parking, providing a safer environment for vehicles and personnel.
[0072] In the above-mentioned exemplary embodiment, the backfill construction method for the highway subgrade in the desert area adopts the aeolian sand dry-pressing construction technology, which takes sand on site and turns waste into treasure, solves the problem of long-distance transportation of backfill materials in the desert area and increases construction costs, and also overcomes the difficulties of water scarcity and shortage of engineering water.
[0073] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0074] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.
Claims
1. A method for filling and constructing a highway subgrade in a desert area, characterized in that: include: S1. Surveying and setting out: Determine the location, shape and size of the roadbed in desert areas; S2, surface clearing: clearing the surface vegetation, humus, garbage and sand layers that do not meet the requirements of roadbed filling within the scope of highway roadbed construction. The surface clearing width is greater than the designed road surface width; S3. Construction of construction access roads: Use red soil and gravel to build construction access roads. The built construction access roads are close to the edge of the highway subgrade and are constructed together with the wind erosion prevention edging. Set up car-passing platforms at set intervals on the construction access roads; S4. Red soil gravel edging: The anti-wind erosion red soil gravel edging is transported by dump trucks and flattened by bulldozers and graders. The wind erosion red soil gravel edging is leveled and rolled together with the subsequent backfill of aeolian sand; S5. Filling of aeolian sand: The aeolian sand backfill adopts the method of stationing platforms outside the slope. A platform is built at a set distance beside the roadbed. The bulldozer pushes the aeolian sand to the front of the platform, and then the loader transports it to the roadbed and fills and compacts it in layers. S6. Leveling and rolling: Use a roller to roll the road according to the steps of stabilizing pressure, leveling, initial rolling, repeated rolling and final rolling. Roll the road first at the edge and then in the middle, first fast and then slow. Control the number of rolling passes to 1-2 times and the total number of rolling passes to 8-10 times. S7. Fill and seal the top layer: Use red soil and gravel to seal the top layer.
2. The method for constructing a roadbed in a desert area according to claim 1, characterized in that: Step S1 specifically includes: S11. Construction preparation: obtain topographic maps, geological survey reports and highway engineering design documents of desert areas, and calibrate measuring instruments; S12, control point re-survey and encryption: re-survey the control points provided in the highway engineering design documents, compare the measured data with the original data, and encrypt the original control points based on the shape, length, width and terrain characteristics of the highway subgrade. The encrypted points are evenly distributed along the highway route, and GPS-RTK technology is used for plane and elevation control measurement; S13, centerline stakeout: According to the coordinates and direction of the centerline of the highway in the highway engineering design documents, use GPS-RTK technology to determine the starting point, end point and turning point of the centerline of the roadbed on the spot. After confirming that the accuracy of the centerline points meets the quality standards, set up wooden or concrete stakes and mark the numbers and mileage stakes; S14. Stake setting out of roadbed side piles: Calculate the side pile positions based on the designed roadbed width, side slope gradient and centerline pile elevation, and use GPS-RTK technology to stake out the side pile positions. After the side pile positions are determined, set up obvious signs and marks, and regularly review and adjust the side pile positions. S15. Leveling and elevation control: Set leveling points within the construction scope to form a closed or attached leveling route, use a level to measure the elevation difference according to the set leveling accuracy requirements, record the elevation data, control the elevation of each part of the roadbed according to the leveling points, and set elevation marks on the side piles or center line piles.
3. The method for constructing a roadbed in a desert area according to claim 2, characterized in that: Step S2 specifically includes: S21. Vegetation cleaning: uproot or remove plants within the scope of highway roadbed construction, and clean up humus soil; S22, sand layer cleaning: remove the sand layer that is too loose and contains a lot of salt on the surface, and clean it to a set depth so that the remaining sand layer can provide sufficient bearing capacity for the highway subgrade; S23. Garbage and obstacle removal: clearing garbage and obstacles that affect construction in the construction area; S24. Site leveling: Flatten the cleaned site surface to meet the basic shape requirements for roadbed filling.
4. The method for constructing a roadbed in a desert area according to claim 1, characterized in that: In step S5, a platform is built on the roadbed every 30-50 m, and the thickness of each layer of compacted aeolian sand is controlled to be 30-50 cm.
5. The method for constructing a roadbed in a desert area according to claim 4, characterized in that: In step S5, the virtual spreading coefficient of the aeolian sand is between 1.2 and 1.3, and the maximum dry density of the aeolian sand is 1.71 g / cm 3 The thickness of the aeolian sand in the bottom layer should be relatively large and controlled at nearly 50cm.
6. The method for constructing a roadbed in a desert area according to claim 1, characterized in that: In step S2, the clearing width is twice the designed road surface width.
7. The method for constructing a roadbed in a desert area according to claim 1, characterized in that: In step S3, the construction access road is constructed with a width of 3.5m and a thickness of 20-30cm, and a vehicle passing platform is set every 200m on the construction access road.
8. The method for constructing a roadbed in a desert area according to claim 1, characterized in that: In step S6, adjacent rolling wheel tracks overlap by 0.2-0.3 m.
9. The method for constructing a highway subgrade in a desert area according to any one of claims 1 to 8, characterized in that: In step S6, the road roller is a Caterpillar CS76 XT self-propelled vibratory roller, which can independently walk and work on the formed sand base surface.
10. The method for constructing a highway subgrade in a desert area according to any one of claims 1 to 8, characterized in that: In step S5, in the excavation area of high sand dunes, a high-power bulldozer is selected to push away the aeolian sand in the downwind direction and roughly level it.