CN116676822A - Saline soil roadbed structure considering freeze thawing cycle effect and construction method - Google Patents

Abstract

The embodiment of the invention discloses a saline soil roadbed structure taking freeze thawing cycle effect into consideration and a construction method. Wherein, the salinized soil layer includes salinized soil layer, well salinized soil layer and lower salinized soil layer, and the gravel hinders salt and separates the layer and includes that first gravel hinders salt and separates the layer and second gravel hinders salt and separates the layer, and geotechnique's cloth includes first geotechnique's cloth and second geotechnique's cloth. The saline soil roadbed is provided with an insulating layer, so that the damage of water salt to the roadbed structure due to the freeze-thawing cycle is weakened. The roadbed slope is provided with a slope soil layer, vegetation is planted, and the growth of the vegetation is guaranteed through the water collecting tank and the drip irrigation belt, so that the stability of the saline soil roadbed slope is guaranteed. The saline soil layer is provided with a drainage ditch, and water salt which is migrated and enriched in the gravel salt-blocking isolation layer is discharged out of the saline soil roadbed. The invention effectively controls the occurrence of the saline soil subgrade diseases in the freeze-thawing cycle state, and prolongs the service life of municipal road engineering in the saline soil area.

Description

Saline soil roadbed structure considering freeze thawing cycle effect and construction method

Technical Field

The invention relates to the technical field of municipal road engineering, in particular to a salty soil roadbed structure considering freeze thawing cycle effect and a construction method.

Background

With the continuous and rapid advancement of national infrastructure construction, the center of gravity of the whole construction is gradually shifted to the northwest saline soil area. The unique environmental climate conditions in northwest regions form larger temperature differences, particularly extreme air temperature occurrence caused by global warming, so that the saline soil roadbed is in a freeze-thawing circulation state under the extreme temperature difference conditions. The saline soil is used as special soil, has strong sensitivity to external factors such as temperature, groundwater, precipitation and the like, causes the saline soil to have many disease problems such as frost heaving, salt swelling, subsidence, slurry turning and the like, and seriously influences the engineering quality of the saline soil subgrade, thereby bringing great losses to the life safety and property safety of people.

The traditional salinized soil roadbed structure and construction method reduce roadbed damage mostly through a waterproof salt control mode, and can not fundamentally and effectively solve the problem of diseases of the salinized soil roadbed under the multi-field coupling effect of temperature, moisture, salt and the like. Therefore, the saline soil roadbed structure taking the freeze thawing cycle effect into consideration and the construction method solve the problems, and simultaneously provide effective technical support for corresponding engineering construction, thereby having great significance.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a saline soil roadbed structure taking the freeze thawing cycle effect into consideration and a construction method.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the utility model provides a take into account salting soil roadbed structure of freeze thawing circulation effect, including the salting soil layer, the gravel hinders salt and separates the fault, geotechnique's cloth, heat preservation and side slope soil layer, wherein, the salting soil layer is including the lower salting soil layer that stacks up the setting from bottom to top, well salting soil layer and last salting soil layer, the gravel hinders between salt soil layer and the lower salting soil layer in between the well salting soil layer, the geotechnique's cloth sets up in the gravel and hinders salt and separates fault top and below, the heat preservation covers in last salting soil layer top, side slope soil layer sets up at the horizontal both ends of salting soil layer.

As a preferable technical scheme of the invention, the gravel salt-blocking partition layer comprises a first gravel salt-blocking partition layer and a second gravel salt-blocking partition layer, wherein the first gravel salt-blocking partition layer is arranged between an upper salinized soil layer and a middle salinized soil layer, the second gravel salt-blocking partition layer is arranged between the middle salinized soil layer and a lower salinized soil layer, the first gravel salt-blocking partition layer and the second gravel salt-blocking partition layer are obliquely arranged from two sides to the center and downwards, and the inclination gradient is 2%.

The technical scheme is that the geotechnical cloth comprises a first geotechnical cloth and a second geotechnical cloth, wherein the first geotechnical cloth is provided with two layers and covers the upper portion and the lower portion of the first gravel salt-resistant isolation layer respectively, the second geotechnical cloth is provided with two layers and covers the upper portion and the lower portion of the second gravel salt-resistant isolation layer respectively, and the inclination gradient of the first geotechnical cloth and the second geotechnical cloth is 2%.

According to the technical scheme, the first geotextile and the second geotextile adopt SNG-PP-300 type polypropylene needled non-woven geotextile, and the geotextile is reversely wrapped and anchored for 2m.

Above-mentioned technical scheme is further, is provided with the escape canal along the salinized soil roadbed direction in first ovum gravel salt blocking separating layer and second ovum gravel salt blocking separating layer's toe position department to excavate on the side slope soil layer and have the hole that dams, be provided with the header tank in the hole that dams, the escape canal passes through the drain pipe and is connected with the header tank, and the outlet of header tank bottom lateral wall is connected with the drip irrigation zone. The drip irrigation belt is paved downwards along the soil layer surface of the side slope, the soil layer gradient of the side slope is 1:1.75, and vegetation is planted on the surface.

Above-mentioned technical scheme still further, water header top one side is provided with the inclined plane, and the inclined plane bottom is provided with the catchment district, and the catchment district is by the grid structure that a plurality of hexagon units pass through the filter concatenation formation. The hexagonal unit includes the hexagon frame, is provided with the disc at hexagon frame center, is provided with a plurality of bracing pieces between disc lateral wall and hexagon frame inner wall to be provided with the top on the disc and be spherical center post, hexagon frame top parcel has the waterproof cloth, and waterproof cloth central point puts the top on the center post, thereby forms the umbrella-shaped unit that center is high and the edge is low, and the filter sets up between two continuous hexagon frames.

As another preferable technical scheme of the invention, a side slope geogrid is arranged between a side slope soil layer and a salinized soil roadbed, the side slope geogrid adopts a bidirectional polypropylene geogrid, a drainage ditch is arranged at a position 2m away from a side slope soil layer slope foot, and the gradient is set to be 1:1.5.

As another preferable technical scheme of the invention, the heat insulation layers are obliquely arranged from two sides to the center upwards, and the road arch gradient is 2%.

The invention also provides a construction method of the saline soil roadbed structure considering the freeze thawing cycle effect, which comprises the following steps:

s1, cleaning a site and performing substrate treatment, and determining filling positions of saline soil roadbed and excavation positions of drainage side ditches by measuring paying-off;

s2, paving a lower salinized soil layer in a layered manner, arranging a drainage ditch and a drainage pipe at the position of the central line of the roadbed, and leveling and rolling the lower salinized soil layer by adopting a TYG200 bulldozer and a YZ20T road roller respectively;

s3, paving and compacting the first gravel salt-blocking isolation layer in a layered manner, respectively arranging first geotextiles on the upper side and the lower side of the first gravel salt-blocking isolation layer before and after construction, and reversely wrapping and anchoring;

s4, repeating the work of the S2 and the S3 to sequentially finish the construction of the middle saline soil layer, the second gravel salt-resistant isolation layer, the second geotextile, the upper saline soil layer, the drainage ditch and the drainage pipe;

s5, pouring foam concrete at the top of the upper salinized soil layer, and curing after pouring and molding;

s6, laying side slope geogrids on two sides of the saline soil roadbed, paving and compacting side slope soil layers in a layered mode, digging a closure pit on the slope of the side slope soil layers, arranging a water collecting tank in the closure pit, burying the bottom of the water collecting tank in the side slope soil layers, and connecting the water collecting tank with a drain pipe;

and S7, excavating a drainage side ditch after the construction of the saline soil roadbed is completed.

Compared with the prior art, the invention has the following advantages:

(1) According to the invention, the gravel salt blocking isolation layer is arranged above each layer of salinized soil layer, when the environment is in a low-temperature environment, salt is blocked from migrating to a freezing layer along with moisture due to capillary action, when the environment is in a high-temperature environment, the way that water salt migrates upwards due to transpiration is blocked, the slope is inclined from top to bottom, the inclination gradient is 2%, so that the salt water is gathered to a slope toe to flow into a drainage ditch, the drainage pipe flows into a water collecting tank, the water collecting tank not only collects the salt water moving upwards in the salinized soil layer, but also collects rainwater through a water collecting area at the top, and then the water collecting tank irrigates vegetation on a slope soil layer through a drip irrigation belt, thereby preventing the loss condition of the slope soil layer and reinforcing the salinized soil subgrade slope;

(2) The geotextile is arranged to play a role in filtering, water permeation, protection and reinforcement;

(3) According to the invention, the drainage ditch is arranged, so that the salt, water and underground water which are enriched in the salt-blocking isolation layer of the gravel and are migrated due to capillary action and transpiration are collected and discharged out of the saline soil roadbed;

(4) The heat-insulating layer is arranged, so that the capability of migrating water salt to the surface layer of the saline soil roadbed due to capillary action and transpiration is weakened, and salt enrichment on the surface layer of the saline soil roadbed is avoided;

(5) According to the invention, the side slope soil layer is arranged, the saline soil roadbed side slope is reinforced, the saline soil roadbed side slope is prevented from being invaded by precipitation, and the stability of the saline soil roadbed is ensured;

(6) The invention is provided with drainage ditches, collects surface precipitation and eliminates the precipitation from the saline soil subgrade.

Drawings

FIG. 1 is a schematic diagram of a salinized soil subgrade structure taking into consideration freeze-thawing cycle effects.

Fig. 2 is a transverse sectional view of a salty soil subgrade structure taking the freeze-thawing cycle effect into consideration.

FIG. 3 is a schematic view of a side slope of a salty soil subgrade structure taking into account freeze-thaw cycle.

Fig. 4 is a schematic view of a header tank in the present invention.

Fig. 5 is a schematic view of a hexagonal frame in the header tank.

Fig. 6 is a side view of the connection of the above-mentioned hexagonal unit of water collection area with the filter plate.

Fig. 7 is a schematic view of the filter plate in the header tank.

In the figure: 1. salting the soil layer; 101. a salinized soil layer is planted; 102. a medium saline soil layer; 103. coating a salinized soil layer; 2. salt-blocking isolating layer of the gravel; 201. a first gravel salt rejection layer; 202. a second gravel salt rejection layer; 3. geotextile; 301. a first geotextile; 302. a second geotextile; 4. a heat preservation layer; 5. a side slope soil layer; 6. a drainage ditch; 7. a drain pipe; 8. a water collection tank; 801. an inclined plane; 802. hexagonal cells; 803. a filter plate; 804. a water outlet; 805. fixing the column; 806. an arc-shaped filter screen; 9. a closure pit; 10. a drain gutter; 11. a drip irrigation belt; 12. a hexagonal frame; 13. a disc; 14. a support rod; 15. a center column; 16. and a fixing hole.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

As shown in figure 1, the saline soil roadbed structure taking the freeze thawing cycle effect into consideration comprises a saline soil layer 1, a gravel salt-blocking layer, geotextiles, a heat preservation layer 4 and a side slope soil layer 5. Wherein, salinized soil layer 1 includes last salinized soil layer 103, well salinized soil layer 102 and lower salinized soil layer 101, and the gravel hinders salt and separates layer including first gravel and hinder salt and separate layer 201 and second gravel and hinder salt and separate layer 202, and geotechnique's cloth includes first geotechnique's cloth 301 and second geotechnique's cloth 302.

Wherein, the fillers of the upper salinized soil layer 103, the middle salinized soil layer 102 and the lower salinized soil layer 101 are all modified and solidified salinized soil, and the water content thereof is close to the optimal water content range. The filling thickness of the salinized soil layer is 200mm, each side of the filling width is widened by 500mm on the basis of the design value, and the filling height depends on actual engineering. The saline soil layer construction machine adopts a TYG200 type bulldozer and a YZ20T type road roller.

The grain composition range of the first gravel salt-blocking separation layer 201 and the second gravel salt-blocking separation layer 202 is 2-5 mm, the grain composition content is more than 75%, and the thickness is 300-500 mm. The first geotextile 301 and the second geotextile 302 are SNG-PP-300 type polypropylene needled non-woven geotextile, and the geotextile is reversely wrapped and anchored for 2m.

The first gravel salt-blocking isolation layer 201 is arranged between the upper salinized soil layer 103 and the middle salinized soil layer 102, the second gravel salt-blocking isolation layer 202 is arranged between the middle salinized soil layer 102 and the lower salinized soil layer 101, and the first gravel salt-blocking isolation layer 201 and the second gravel salt-blocking isolation layer 202 are arranged from two sides to the center and are inclined downwards, and the inclination gradient is 2%.

The first geotextile 301 is provided with two layers and covers above and below the first gravel salt-blocking partition layer 201, respectively, the second geotextile 302 is provided with two layers and covers above and below the second gravel salt-blocking partition layer 202, respectively, and the inclination of the first geotextile 301 and the second geotextile 302 is 2%. At least 2 gravel salt-blocking layers and 4 geotextiles are arranged on the saline soil subgrade.

As shown in fig. 2, drainage ditches 6 along the direction of the salty soil roadbed are arranged at the positions of the bottoms of the first and second gravel salt-blocking separation layers 201 and 202, a closure pit 9 is dug on the side slope soil layer 5, a water collection tank 8 is arranged in the closure pit 9, the drainage ditches 6 are connected with the water collection tank 8 through drainage pipes 7, and a drainage outlet 804 on the side wall of the bottom of the water collection tank 8 is connected with a drip irrigation belt 11 as shown in fig. 3. The drip irrigation belt 11 is paved downwards along the surface of the side slope soil layer 5, and vegetation is planted on the surface of the side slope soil layer 5.

The heat preservation layer 4 is arranged obliquely upwards from two sides to the center, foam concrete is adopted as the material, and the road arch gradient is set to be 2%. The filler of the side slope soil layer 5 is gravel-containing low-liquid-limit clay, the filling thickness is 200mm, the slope gradient is set to be 1:1.75, and the surface of the side slope soil layer 5 is a vegetation greening area. A side slope geogrid is arranged between the side slope soil layer 5 and the saline soil roadbed, the side slope geogrid adopts a bidirectional polypropylene geogrid, a drainage side ditch 10 is arranged at a position 2m away from the side slope soil layer 5 and the slope is set to be 1:1.5.

As shown in fig. 4, an inclined plane 801 is provided on one side of the top of the water collection tank 8, a water collection area is provided on the bottom of the inclined plane 801, and the water collection area is a grid structure formed by splicing a plurality of hexagonal units 802 through filter plates 803. As shown in fig. 5, the hexagonal unit 802 includes a hexagonal frame 12, a circular disk 13 is disposed at the center of the hexagonal frame 12, a plurality of support rods 14 are disposed between the side walls of the circular disk 13 and the inner wall of the hexagonal frame 12, a center column 15 having a spherical top is disposed on the circular disk 13, a waterproof cloth is wrapped over the hexagonal frame 12, and the center of the waterproof cloth is pushed against the center column 15, thereby forming an umbrella-shaped unit having a high center and a low edge, and a filter plate 803 is disposed between the two connected hexagonal frames 12.

As shown in fig. 5 and 7, fixing columns 805 are disposed on front and rear sides of two ends of the filter plate 803, and the fixing columns 805 are connected with the fixing holes 16 on the side wall of the hexagonal frame 12 to connect two adjacent hexagonal units 802, so as to form a water collecting structure with multiple small umbrella-shaped structures connected in series. On the one hand, rainwater flows into the water collection tank 8 along with the inclined plane 801 and flows into the filtering plate 803 between the adjacent hexagonal units 802, and when the rainwater falls onto the hexagonal units 802, the rainwater flows into the water collection tank 8 from the filtering plate 803 along with the sliding of the umbrella top to the umbrella feet because the hexagonal units 802 are of umbrella-shaped structures. And the water in the water collection tank 8 irrigates the vegetation on the surface through the drip irrigation belt 11, thereby achieving the purpose of solidifying the slope and preventing the vegetation on the slope from dying due to drought weather.

As shown in fig. 3, the water collection tank 8 is arranged on the side slopes on both sides of the saline soil roadbed, and the water collection tank 8 is also arranged at the top of the side slope, and the water collection tank 8 at the top is mainly used for collecting rainwater, the water collection area at the top of the water collection tank 8 is designed into a structure that a plurality of hexagonal units 802 are sequentially connected through the filter plates 803, on one hand, stones or sundries such as tree stems or leaves can be isolated and fall into the water collection tank 8, thereby blocking the water outlet 804, and meanwhile, the hexagonal units 802 are designed into an umbrella-shaped structure, so that rainwater is convenient to collect. Thereby realizing the purpose of quickly collecting rainwater while blocking sundries.

As shown in fig. 6, in order to prevent the filter plate 803 from being blocked by the falling of debris such as stones/tree poles and leaves, a downward concave arc-shaped filter screen 806 is fixed above the filter plate 803, and the upper ends of both sides of the arc-shaped filter screen 806 are extended and bent toward the waterproof cloth on both sides to form an inclined section in accordance with the inclination direction of the waterproof cloth. Sundries such as leaves, branches or stones falling onto the waterproof cloth can slide downwards along the inclination direction of the waterproof cloth, and as the inclination angle of the inclination section is consistent with that of the current position of the waterproof cloth, the sundries can slide onto the arc-shaped filter screen 806 along the inclination section, so that the filter plate 803 below the arc-shaped filter screen 806 is not blocked, a gap through which rainwater passes is reserved between the inclination section and the waterproof cloth on two sides, and rainwater can smoothly flow onto the filter plate 803 below.

The drip irrigation belt can adopt a tee joint structure or a Y-shaped structure.

The saline soil roadbed construction method comprises the following steps:

step S1, cleaning a site and performing substrate treatment, and determining filling positions of the saline soil roadbed and excavation positions of the drainage ditches 10 by measuring and paying-off;

s2, paving the lower salinized soil layer 101 in a layered manner, arranging a drainage ditch 6 and a drainage pipe 7 at the position of the central line of the roadbed, and leveling and rolling the lower salinized soil layer 101 by adopting a TYG200 bulldozer and a YZ20T road roller respectively;

s3, paving and compacting the first gravel salt-blocking isolation layer 201 in a layered manner, respectively arranging first geotextiles 301 on the upper side and the lower side of the first gravel salt-blocking isolation layer 201 before and after construction, and reversely wrapping and anchoring;

s4, repeating the work of S2 and S3 to sequentially finish the construction of the middle salinized soil layer 102, the second gravel salt-blocking isolation layer 202, the second geotextile 302, the upper salinized soil layer 103, the drainage ditch 6 and the drainage pipe 7;

s5, pouring foam concrete at the top of the upper salinized soil layer 103, and curing after pouring and molding;

s6, laying side slope geogrids on two sides of a saline soil roadbed side slope, paving and compacting side slope soil layers 5 in a layered mode, digging a closure pit 9 on the slope of the side slope soil layers 5, arranging a water collecting tank 8 in the closure pit 9, burying the bottom of the water collecting tank 8 in the side slope soil layers 5, and connecting with a drain pipe 7;

and S7, after the construction of the saline soil roadbed is finished, excavating a drainage ditch 10, and planting vegetation on the side slope.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. The utility model provides a take into account salting soil roadbed structure of freeze thawing circulation effect, a serial communication port, including the salting soil layer, the gravel salt isolation layer that hinders, geotechnique's cloth, heat preservation and side slope soil layer, wherein, the salting soil layer is including the lower salting soil layer that stacks up the setting from bottom to top, well salting soil layer and last salting soil layer, the gravel salt isolation layer that hinders sets up between last salting soil layer and well salting soil layer, well salting soil layer and lower salting soil layer, geotechnique's cloth sets up in gravel salt isolation layer top and below, the heat preservation covers in last salting soil layer top, side slope soil layer sets up at the horizontal both ends of salting soil layer.

2. The saline soil subgrade structure considering freeze thawing cycle action according to claim 1, wherein the gravel salt blocking layer comprises a first gravel salt blocking layer and a second gravel salt blocking layer, the first gravel salt blocking layer is arranged between an upper saline soil layer and a middle saline soil layer, the second gravel salt blocking layer is arranged between the middle saline soil layer and a lower saline soil layer, and the first gravel salt blocking layer and the second gravel salt blocking layer are arranged from two sides to the center and are inclined downwards, and the inclination gradient is 2%.

3. The salty soil subgrade structure considering the freeze-thaw cycle action according to claim 2, wherein the geotextile comprises a first geotextile and a second geotextile, the first geotextile is provided with two layers and covers above and below the first gravel salt blocking layer, respectively, the second geotextile is provided with two layers and covers above and below the second gravel salt blocking layer, respectively, and the inclination of the first geotextile and the second geotextile is 2%.

4. A salty soil subgrade structure considering freeze thawing cycle effect according to claim 3, wherein the first geotextile and the second geotextile are SNG-PP-300 type polypropylene needled nonwoven geotextile, and the geotextile is reversely wrapped and anchored for 2m.

5. The saline soil subgrade structure considering the freeze thawing cycle effect according to claim 2, characterized in that drainage ditches along the direction of the saline soil subgrade are arranged at the positions of the slope feet of the first and second gravel salt-blocking layers, a closure pit is excavated on a slope soil layer, a water collecting tank is arranged in the closure pit, the drainage ditches are connected with the water collecting tank through drainage pipes, a drain outlet on the side wall of the bottom of the water collecting tank is connected with a drip irrigation belt, the drip irrigation belt is paved downwards along the surface of the slope soil layer, the slope soil layer gradient is 1:1.75, and vegetation is planted on the surface.

6. The salty soil subgrade structure considering the freeze thawing cycle effect according to claim 5, wherein an inclined plane is arranged on one side of the top of the water collection tank, a water collection area is arranged at the bottom of the inclined plane, and the water collection area is a grid structure formed by splicing a plurality of hexagonal units through filter plates.

7. The salty soil subgrade structure considering the freeze-thawing cycle effect according to claim 6, wherein the hexagonal unit comprises a hexagonal frame, a disc is arranged at the center of the hexagonal frame, a plurality of supporting rods are arranged between the side wall of the disc and the inner wall of the hexagonal frame, a center column with a spherical top is arranged on the disc, waterproof cloth is wrapped above the hexagonal frame, the center position of the waterproof cloth is propped against the center column, thereby forming an umbrella-shaped unit with a high center and a low edge, and the filter plate is arranged between the two connected hexagonal frames.

8. The saline soil subgrade structure considering the freeze thawing cycle effect according to claim 1, characterized in that a side slope geogrid is arranged between a side slope soil layer and the saline soil subgrade, the side slope geogrid adopts a bidirectional polypropylene geogrid, a drainage ditch is arranged at a position 2m away from a side slope soil layer slope foot, and the gradient is set to be 1:1.5.

9. The construction of claim 1, wherein the insulation layer is disposed obliquely upward from both sides to the center, and has an arch slope of 2%.

10. The construction method of a salty soil subgrade structure considering the freeze-thawing cycle effect according to any one of claims 1 to 9, which is characterized by comprising the following steps:

s1, cleaning a site and performing substrate treatment, and determining filling positions of saline soil roadbed and excavation positions of drainage side ditches by measuring paying-off;

s2, paving a lower salinized soil layer in a layered manner, arranging a drainage ditch and a drainage pipe at the position of the central line of the roadbed, and leveling and rolling the lower salinized soil layer by adopting a TYG200 bulldozer and a YZ20T road roller respectively;

s3, paving and compacting the first gravel salt-blocking isolation layer in a layered manner, respectively arranging first geotextiles on the upper side and the lower side of the first gravel salt-blocking isolation layer before and after construction, and reversely wrapping and anchoring;

s4, repeating the work of the S2 and the S3 to sequentially finish the construction of the middle saline soil layer, the second gravel salt-resistant isolation layer, the second geotextile, the upper saline soil layer, the drainage ditch and the drainage pipe;

s5, pouring foam concrete at the top of the upper salinized soil layer, and curing after pouring and molding;

s6, laying side slope geogrids on two sides of the saline soil roadbed, paving and compacting side slope soil layers in a layered mode, digging a closure pit on the slope of the side slope soil layers, arranging a water collecting tank in the closure pit, burying the bottom of the water collecting tank in the side slope soil layers, and connecting the water collecting tank with a drain pipe;

and S7, excavating a drainage side ditch after the construction of the saline soil roadbed is completed.