Supporting structure for repairing embankment slope and construction method

Abstract

The invention discloses a supporting structure for repairing an embankment slope and a construction method. The construction method comprises the following steps: preliminarily leveling a collapsed embankment, and tamping until the compaction degree is not less than 92%; micro steel pipe piles are driven into the first-aid repair subgrade area; a first graded broken stone hardcore is laid on the upper portions of the miniature steel pipe piles; a first sand cushion layer is laid on the first graded broken stone hardcore layer; first geotechnical cloth is laid on the sand cushion layer; laying a geomembrane on the first geotechnical cloth to form a drainage layer; second geotechnical cloth is laid on the geomembrane; a second sand cushion layer is laid on the second geotechnical cloth; a second graded broken stone hardcore is laid on the upper portion of the second sand hardcore; a plurality of gabions are hoisted on the upper portion of the second-grade broken stone hardcore; a grass blanket is laid between the original roadbed area and the first-aid repair roadbed area; stone blocks are thrown between the gabion retaining wall and the original roadbed area for underlying; a third-grade broken stone hardcore is laid on the upper portions of the stones; and after rolling is completed, a base layer and a pavement structure are constructed finally.

Description

Technical Field

[0001] The present invention relates to the field of road repair, and particularly to a support structure and construction method for quickly repairing the embankment slope. Background Art

[0002] Currently, affected by global warming, extreme climates occur frequently, and continuous heavy rains often occur in some local areas, resulting in rainwater seeping into the roadbed. For some embankment slopes filled with clay, under the long-term action of rainwater immersion, the stability of the embankment slope drops sharply, and then local collapse of the embankment occurs. Especially for some high and steep embankments, the problem of slope instability is more serious. After the embankment slope collapses, it often leads to traffic interruption, which has a serious impact on the lives, economic development and social operation of local residents. Quickly repairing and reopening the collapsed embankment slope can effectively reduce the adverse effects caused by traffic interruption.

[0003] However, currently, the repair of collapsed embankments still mainly adopts traditional forms such as retaining walls, anti-slide piles and lattice beams. Although these support means can effectively control the failure of the embankment, basically, they can only be reopened after the concrete or cement forms strength, which takes a long time and is not suitable for sections that need to be reopened quickly, especially for the emergency repair of some traffic lifelines. Summary of the Invention

[0004] In view of this, the embodiment of the present invention provides a construction method for a support structure of a quickly repaired embankment slope, which has the characteristics of fast construction, wide material sources, easy quality control and integrated protection.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] In a first aspect, the embodiment of the present invention provides a support structure method for a quickly repaired embankment slope, including:

[0007] Step S1, preliminarily leveling the collapsed embankment and ramming it to a compaction degree of not less than 92%;

[0008] Step S2, driving micro steel pipe piles in the area of the quickly repaired roadbed;

[0009] Step S3, laying a first graded gravel cushion on the upper part of the micro steel pipe piles;

[0010] Step S4, laying a first sand cushion on the first graded gravel cushion;

[0011] Step S5, laying a first geotextile on the sand cushion;

[0012] Step S6, laying a geomembrane on the first geotextile to form a drainage layer;

[0013] Step S7, laying a second geotextile on the geomembrane;

[0014] Step S8: Lay a second sand cushion layer on the second geotextile.

[0015] Step S9: Lay a second graded crushed stone cushion layer on the upper part of the second sand cushion layer.

[0016] Step S10: Hoist and install multiple gabions on the upper part of the second graded crushed stone cushion layer.

[0017] Step S11: Lay a grass carpet between the original roadbed area and the emergency repair roadbed area.

[0018] Step S12: Construct a bottom layer of stones between the gabion retaining wall and the original roadbed area.

[0019] Step S13: Lay a third graded crushed stone cushion layer on the upper part of the stones.

[0020] Step S14: After compaction, finally construct the base course and pavement structure.

[0021] Preferably, driving the micro steel pipe piles in the emergency repair roadbed area includes:

[0022] Drive multiple micro steel pipe piles into the bearing layer of the emergency repair roadbed area by more than 0.5 m. The micro steel pipe piles are arranged in a rectangular or plum blossom shape, and the longitudinal and transverse row spacing is not less than 3d 1 , d 1 is the outer diameter of the micro steel pipe pile.

[0023] Preferably, the spacing of the micro steel pipe piles is calculated as follows:

[0024] E cs = mE p +(1 - m)E s (1)

[0025]

[0026] where E p is the compression modulus of the pile, E s is the compression modulus of the soil, E cs is the composite compression modulus, m is the replacement ratio, A is the area of the reinforced soil mass, A P represents the cross-sectional area of the steel pipe, d 1 is the outer diameter of the steel pipe pile, d 2 is the inner diameter of the steel pipe pile, y is the pile spacing, F is the vertical force on the upper part of the steel pipe pile, F Rz is the shear force on the steel pipe pile. The area of the steel pipe pile takes the larger value from Equation (3) and Equation (4).

[0027] Preferably, hoisting and installing multiple gabions on the upper part of the second graded crushed stone cushion layer includes:

[0028] The gabions are in the shape of a fabricated cuboid. The gabions are connected together with bayonets or steel wires to form a whole, and a gabion retaining wall is made. Among them, the connection spacing does not exceed 20 cm, and tensioning is set every 10 - 40 cm.

[0029] Preferably, the method further includes:

[0030] The anti - slip check calculation and anti - overturn check calculation should be carried out on the gabion retaining wall to determine that the requirements of the anti - slip check calculation and anti - overturn check calculation are met, and the corresponding number of gabion layers and the weight corresponding to each layer of gabions are obtained.

[0031] Preferably, the anti - slip check calculation and anti - overturn check calculation include:

[0032] Anti - slip check calculation:

[0033]

[0034] Anti - overturn check calculation:

[0035]

[0036] Wherein:

[0037]

[0038] F a is the anti - slip stability coefficient, F t is the anti - overturn stability coefficient, μ is the friction coefficient between the gabion and the base, G n is the total gravity of n - layer gabions, x n is the distance from the centroid of the nth layer of gabions to the toe of the gabion retaining wall, E ai is the active earth pressure of the i - th layer of fill; r 1 、r 2 、H 1 、H 2 、K a1 、K a2 、z 1 and z 2 are respectively the unit weight, height, active earth pressure coefficient and the distance from the active earth pressure to the base of the 1st and 2nd layers of fill, and q is the upper load.

[0039] Preferably, the method further includes:

[0040] A precast catch - water ditch is constructed in the area of the gabion retaining wall far from the original roadbed. The catch - water ditch is communicated with the drainage layer to drain the accumulated water in the roadbed.

[0041] Preferably, the thickness of the first sand cushion layer and the second sand cushion layer is 5 cm - 10 cm.

[0042] Preferably, the thicknesses of the first graded crushed stone cushion layer and the second graded crushed stone cushion layer are 15 cm to 20 cm, and the thickness of the third graded crushed stone cushion layer is greater than 30 cm.

[0043] In a second aspect, an embodiment of the present invention further provides a structure formed by the method for supporting the slope of a rush-repair embankment described in any one of the above. The structure includes: a rush-repair roadbed area, in which there are a plurality of micro steel pipe piles under the rush-repair roadbed area. The upper part of the micro steel pipe piles is a first graded crushed stone cushion layer, on which there is a first sand cushion layer, on which there is a first geotextile, and on which there is a geomembrane to form a drainage layer; on the geomembrane there is a second geotextile, on which there is a second sand cushion layer, on which there is a second graded crushed stone cushion layer, and on the upper part of the second graded crushed stone cushion layer there are a plurality of hoisted gabions. There is a grass carpet between the original roadbed area and the rush-repair roadbed area. Between the gabion retaining wall and the original roadbed area there are stones, and on the upper part of the stones there is a third graded crushed stone cushion layer, and above the third graded crushed stone cushion layer there are a base course and a pavement structure.

[0044] An embodiment of the present invention provides a supporting structure and a construction method for the slope of a rush-repair embankment, including: initially leveling the collapsed embankment slope and ramming it to a compaction degree of not less than 92%; driving micro steel pipe piles in the rush-repair roadbed area; laying a first graded crushed stone cushion layer on the upper part of the micro steel pipe piles; laying a first sand cushion layer on the first graded crushed stone cushion layer; laying a first geotextile on the sand cushion layer; laying a geomembrane on the first geotextile to form a drainage layer; laying a second geotextile on the geomembrane; laying a second sand cushion layer on the second geotextile; laying a second graded crushed stone cushion layer on the upper part of the second sand cushion layer; hoisting a plurality of gabions on the upper part of the second graded crushed stone cushion layer; laying a grass carpet between the original roadbed area and the rush-repair roadbed area; throwing stones at the bottom between the gabion retaining wall and the original roadbed area; laying a third graded crushed stone cushion layer on the upper part of the stones; after ramming is completed, finally constructing the base course and the pavement structure. In this way, this construction method is not affected by the time such as the cementation and hardening of materials, can be constructed quickly and continuously, and all materials are conventional building materials; further, the embodiments of the present invention basically adopt materials such as stones and crushed stones, which can not only support the soil mass in the collapsed area to play a supporting role, but also timely drain the moisture of the soil mass to prevent the embankment from collapsing again, and has the characteristics of fast construction, wide source of materials, easy control of quality and integrated protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic structural diagram of a supporting structure for the slope of a rush-repair embankment provided in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] To better illustrate this embodiment, some components in the accompanying drawings are omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0047] See Figure 1 , an embodiment of the present invention provides a method for supporting the slope of a rush-repair embankment, including:

[0048] Step S1, preliminarily level the collapsed embankment and compact it to a compaction degree of not less than 92%;

[0049] Step S2, drive micro steel pipe piles in the rush-repair subgrade area;

[0050] Step S3, lay a first graded gravel cushion on the upper part of the micro steel pipe piles;

[0051] Step S4, lay a first sand cushion on the first graded gravel cushion;

[0052] Step S5, lay a first geotextile on the sand cushion;

[0053] Step S6, lay a geomembrane on the first geotextile to form a drainage layer;

[0054] Step S7, lay a second geotextile on the geomembrane;

[0055] Step S8, lay a second sand cushion on the second geotextile;

[0056] Step S9, lay a second graded gravel cushion on the upper part of the second sand cushion;

[0057] Step S10, hoist a plurality of gabions on the upper part of the second graded gravel cushion;

[0058] Step S11, lay a grass mat between the original subgrade area and the rush-repair subgrade area;

[0059] Step S12, construct a stone bottom layer between the gabion retaining wall and the original subgrade area;

[0060] Step S13, lay a third graded gravel cushion on the upper part of the stones;

[0061] After compaction, finally construct the base course and pavement structure.

[0062] As can be seen from the above embodiments of the present invention, this construction method is not affected by the time such as the cementation and hardening of materials, can be quickly and continuously constructed, and all materials are conventional building materials; further, the embodiments of the present invention basically adopt materials such as stones and gravels, which can not only support the soil mass in the collapsed area to play a supporting role, but also timely drain the moisture of the soil mass to prevent the embankment from collapsing again, and has the characteristics of fast construction, wide material sources, easy quality control and integrated protection.

[0063] In one embodiment, driving the micro steel pipe piles in the emergency repair subgrade area includes:

[0064] Driving multiple micro steel pipe piles into the bearing stratum of the emergency repair subgrade area by more than 0.5 m, and the micro steel pipe piles are arranged in a rectangular or plum blossom shape, and the longitudinal and transverse row spacings are not less than 3d 1 , d 1 is the outer diameter of the micro steel pipe pile.

[0065] In one embodiment, the spacing of the micro steel pipe piles is calculated as follows:

[0066] E cs = mE p +(1 - m)E s (1)

[0067]

[0068] wherein, E p is the compression modulus of the pile, E s is the compression modulus of the soil, E cs is the composite compression modulus, m is the replacement ratio, A is the area of the reinforced soil mass, A P represents the cross-sectional area of the steel pipe, d 1 is the outer diameter of the steel pipe pile, d 2 is the inner diameter of the steel pipe pile, y is the pile spacing, F is the vertical force on the upper part of the steel pipe pile, F Rz is the shear force received by the steel pipe pile, and the area of the steel pipe pile takes the larger value of formula (3) and formula (4).

[0069] In one embodiment, hoisting a plurality of gabions on the upper part of the second graded crushed stone cushion layer includes:

[0070] The gabions are made into a cuboid shape, and the gabions are connected together with bayonets or steel wires to form an integral body to form a gabion retaining wall, wherein the connection spacing does not exceed 20 cm, and tensioning is provided every 10 - 40 cm.

[0071] In one embodiment, the method further includes:

[0072] The anti-slip check calculation and anti-overturning check calculation shall be carried out on the gabion retaining wall to determine that the requirements of the anti-slip check calculation and anti-overturning check calculation are met, and the corresponding number of gabion layers and the weight corresponding to each gabion layer are obtained.

[0073] In one embodiment, the anti-slip check calculation and anti-overturning check calculation include:

[0074] Anti-slip check calculation:

[0075]

[0076] Anti-overturning check calculation:

[0077]

[0078] Wherein:

[0079]

[0080] F a is the anti-slip stability coefficient, F t is the anti-overturning stability coefficient, μ is the friction coefficient between the gabion and the base, G n is the total gravity of n layers of gabions, x n is the distance from the centroid of the nth layer of gabions to the toe of the gabion retaining wall, E ai is the active earth pressure of the i-th layer of fill; r 1 、r 2 、H 1 、H 2 、K a1 、K a2 、z 1 and z 2 are respectively the unit weight, height, active earth pressure coefficient and the distance from the active earth pressure to the base of the 1st and 2nd layers of fill, and q is the upper load.

[0081] In one embodiment, the method further includes:

[0082] A precast catch drain is constructed in the area of the gabion retaining wall far from the original roadbed, and the catch drain is communicated with the drainage layer to drain the accumulated water in the roadbed.

[0083] In one embodiment, the thickness of the first sand cushion layer and the second sand cushion layer is 5 cm to 10 cm.

[0084] In one embodiment, the thickness of the first graded gravel cushion layer and the second graded gravel cushion layer is 15 cm to 20 cm, and the thickness of the third graded gravel cushion layer is greater than 30 cm.

[0085] The embodiment of the present invention also provides a structure formed by the method for supporting the slope of a rush-repair embankment according to any one of the above, including: a rush-repair subgrade area, with a plurality of micro steel pipe piles under the rush-repair subgrade area. The upper part of the micro steel pipe piles is a first graded gravel cushion layer, the first graded gravel cushion layer is covered with a first sand cushion layer, the sand cushion layer is covered with a first geotextile, and the first geotextile is covered with a geomembrane to form a drainage layer; on the geomembrane is a second geotextile, on the second geotextile is a second sand cushion layer, on the second sand cushion layer is a second graded gravel cushion layer, and on the upper part of the second graded gravel cushion layer are a plurality of hoisted stone cages. There is a grass carpet between the original subgrade area and the rush-repair subgrade area. Between the stone cage retaining wall and the original subgrade area are stones, above the stones is a third graded gravel cushion layer, and above the third graded gravel cushion layer are a base course and a pavement structure.

[0086] The present invention will be further described below through specific embodiments.

[0087] Taking a road section as an example, the height of a collapsed embankment is 3m, and the method of this patent is used for rush repair. The lower layer of the subgrade is padded with 2m thick stones, and the upper layer of the subgrade is filled with 1m thick graded gravel. The specific gravity of the stones is 23kN / m 3 , the internal friction angle is 40°, the specific gravity of the graded gravel is 25kN / m 3 , the internal friction angle is 30°, the cohesion c = 0, the traffic load on the upper part of the subgrade is 60kN / m 2 , the specific gravity of the stone cage is 23kN / m 3 , the friction coefficient μ between the stone cage and the lower gravel cushion layer is 0.55, the bearing capacity of the foundation under the collapsed embankment is 50kPa, and the compression modulus is 0.8MPa.

[0088] (1) Calculation of earth pressure of the gravel layer

[0089] Calculate the active earth pressure coefficient of the gravel layer according to the Rankine theory:

[0090]

[0091] Active earth pressure of the gravel layer:

[0092]

[0093] Position of the action of the active earth pressure:

[0094]

[0095] (2) Active earth pressure of the block stone layer:

[0096] Calculate the active earth pressure coefficient of the gravel layer according to the Rankine theory:

[0097]

[0098] (3) Gravity of the gabion

[0099] Assume the cross-sectional size of the gabion is 1m×1m, and a retaining wall with a height of 3m is built. Initially, 6 gabions can be designed to be stacked in a triangular shape. Then the unit weight of the gabion retaining wall is:

[0100] G S = 6×B 1 ×H 1 ×r 3 = 6×1×1×23 = 138.00kN / m

[0101]

[0102] (4) Anti-overturning check

[0103]

[0104] Therefore, the anti-overturning requirement is met.

[0105] (5) Anti-sliding check

[0106]

[0107] Therefore, the anti-sliding requirement is not met.

[0108] Then it is necessary to continue to increase the weight of the gabion retaining wall. Design the cross-sectional size of the gabion to be 1m×1m, with 2 arranged in the top layer, 3 in the middle layer, and 3 in the bottom layer, for a total of 8 gabions. Then there is:

[0109]

[0110] The anti-sliding requirement is met.

[0111] (6) Foundation bearing capacity check

[0112] Select steel pipe piles with a diameter of 159*8 for the treatment of the gabion foundation. The ultimate shear strength of the steel pipe is τ = 200MPa, and the elastic modulus is 170GPa. Then the outer diameter of the steel pipe pile is 15.9cm, the inner diameter is 151cm, and the spacing is 100cm, arranged in a square pattern. Then the replacement ratio of the micro steel pipe piles is:

[0113]

[0114] Composite compression modulus of the foundation treated with micro steel pipe piles:

[0115] E cs = mE P +(1 - m)E s = 0.00195×170×10 3+(1 - 0.00195)×0.8 = 332.3 MPa

[0116] Bearing capacity of the composite foundation of steel pipe piles

[0117]

[0118] Meets the bearing capacity requirements.

[0119] (7) Shear strength check of steel pipe piles

[0120]

[0121] Meets the shear requirements.

[0122] Through the embodiments of the present invention, in this subgrade emergency repair, 159*8 steel pipe piles are arranged in a square pattern with a spacing of 1 m, the gabions have a cross-section of 1*1 m, and 8 gabions are stacked (2 gabions are arranged in the top layer, 3 in the middle layer, and 3 in the bottom layer, for a total of 8 gabions).

[0123] The above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and scope of the present invention are all included within the protection scope of the present invention.

Claims

1. A method for repairing a supporting structure of an embankment slope, characterized in that: include: Step S1, preliminarily leveling the collapsed embankment and tamping it to a compaction degree of not less than 92%; Step S2, driving micro steel pipe piles into the emergency repair roadbed area; Step S3, laying a first graded crushed stone cushion layer on the upper part of the micro steel pipe pile; Step S4, laying a first sand cushion layer on the first graded crushed stone cushion layer; Step S5, laying a first geotextile on the sand cushion layer; Step S6, laying a geomembrane on the first geotextile to form a drainage layer; Step S7, laying a second geotextile on the geomembrane; Step S8, laying a second sand cushion layer on the second geotextile; Step S9, laying a second graded crushed stone cushion layer on the second sand cushion layer; Step S10, hoisting a plurality of gabions on the upper part of the second graded crushed stone cushion layer; Step S11, laying a grass carpet between the original roadbed area and the emergency repair roadbed area; Step S12, constructing a stone base layer between the gabion retaining wall and the original roadbed area; Step S13, laying a third graded crushed stone cushion layer on the upper part of the stone; Step S14: After the rolling is completed, the base layer and the pavement structure are finally constructed.

2. The method for repairing the supporting structure of the embankment slope according to claim 1 is characterized in that: The step of driving micro steel pipe piles into the emergency roadbed repair area includes: A plurality of micro steel pipe piles are driven into the bearing layer of the emergency repair roadbed area greater than 0.5m, wherein the micro steel pipe piles are arranged in a rectangular or plum blossom shape, and the vertical and horizontal row spacing is not less than 3d1, where d1 is the outer diameter of the micro steel pipe pile.

3. The method for repairing the supporting structure of the embankment slope according to claim 2 is characterized in that: The spacing of the micro steel pipe piles is calculated as follows: HAVE BEEN cs =mE p +(1-m)E s (1) Among them, E p is the compression modulus of the pile, E s is the compression modulus of soil, E cs is the composite compression modulus, m is the replacement rate, A is the area of ​​reinforced soil, A P represents the cross-sectional area of ​​the steel pipe, d2 is the inner diameter of the steel pipe pile, y is the distance between piles, F is the vertical force on the upper part of the steel pipe pile, F Rz is the shear force on the steel pipe pile, and the area of ​​the steel pipe pile is the larger value of equation (3) and equation (4).

4. The method for repairing the supporting structure of the embankment slope according to claim 1 is characterized in that: The method of hoisting a plurality of gabions on the upper part of the second graded crushed stone cushion layer comprises: The gabions are made into rectangular shapes and are connected together with bayonet or steel wire to form a whole, making a gabion retaining wall. The connection spacing does not exceed 20cm, and tensioning is set every 10-40cm.

5. The method for repairing the supporting structure of the embankment slope according to claim 4 is characterized in that: The method further comprises: The gabion retaining wall should be subjected to anti-slip and anti-overturning calculations to ensure that the requirements of anti-slip and anti-overturning calculations are met, and the corresponding number of gabion layers and the weight of each gabion layer are obtained.

6. The method for repairing the supporting structure of the embankment slope according to claim 5, characterized in that: The anti-slip calculation and anti-overturning calculation include: Anti-slip calculation: Anti-overturning calculation: in: F a is the anti-slip stability coefficient, F t is the anti-overturning stability coefficient, μ is the friction coefficient between the gabion and the base, G n is the total gravity of n layers of gabions, x n is the distance between the center of gravity of the nth layer of gabion and the toe of the gabion retaining wall, E ai is the active earth pressure of the i-th fill layer; r1, r2, H1, H2, K a1 , K a2 , z1 and z2 are the bulk density, height, active earth pressure coefficient and distance of active earth pressure from the base of the first and second layers of filling respectively, and q is the upper load.

7. The method for repairing the supporting structure of the embankment slope according to claim 1, characterized in that: The method further comprises: The gabion retaining wall is constructed with a prefabricated drainage ditch away from the original roadbed area, and the drainage ditch is connected to the drainage layer to drain the accumulated water in the roadbed.

8. The method for repairing the supporting structure of the embankment slope according to claim 1, characterized in that: The thickness of the first sand cushion layer and the second sand cushion layer is 5 cm to 10 cm.

9. The method for repairing the supporting structure of the embankment slope according to claim 1, characterized in that: The thickness of the first graded crushed stone cushion layer and the second graded crushed stone cushion layer is 15 cm to 20 cm, and the thickness of the third graded crushed stone cushion layer is greater than 30 cm.

10. A structure formed by the supporting structure method for repairing embankment slope according to any one of claims 1 to 10, characterized in that: include: Emergency repair roadbed area, there are multiple micro steel pipe piles under the emergency repair roadbed area, the upper part of the micro steel pipe piles is the first graded gravel cushion layer, the first graded gravel cushion layer is on the first sand cushion layer, the first geotextile is on the sand cushion layer, and the first geotextile is on the geomembrane to form a drainage layer; the geomembrane is on the second geotextile, the second geotextile is on the second sand cushion layer, the second graded gravel cushion layer is on the second sand cushion layer, and the upper part of the second graded gravel cushion layer is multiple hoisted gabions, a straw carpet is provided between the original roadbed area and the emergency repair roadbed area, there are stones between the gabion retaining wall and the original roadbed area, the upper part of the stones is the third graded gravel cushion layer, and the base layer and pavement structure are above the third graded gravel cushion layer.

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