Three-dimensional partition structure and construction method of high and steep embankment

Abstract

The invention discloses a three-dimensional partition structure and construction method of a high and steep embankment. The three-dimensional partition structure of the high and steep embankment includes an embankment partition structure, an anchoring system and a drainage system. The embankment partition structure is divided into a deformation control area and a shear control area. The shear control area is divided into multiple levels along the vertical direction. The cement content of cement-modified soil used in each level of the shear control area decreases step by step from bottom to top. The shear control area is obtained by layered filling and compaction of cement-modified soil with different cement contents and geogrids. The anchoring system includes a gabion structure on the embankment slope surface to reinforce and protect the soil in the shear control area. The drainage system includes a slope platform drainage ditch, a slope bottom drainage ditch and a longitudinal drainage ditch. The invention is divided into a deformation control area and a shear control area according to the stress characteristics of the embankment, and the shear control area is reinforced in stages, which reduces the settlement deformation of the embankment during use, effectively reduces farmland occupation and house demolition, and reduces engineering costs.

Description

Technical Field

[0001] The invention belongs to the technical field of slope treatment and relates to a three-dimensional partition structure of a high and steep embankment and a construction method. Background Art

[0002] With the rapid development of my country's infrastructure, highway construction projects under construction and renovation and expansion are paying more and more attention to environmental protection. How to save project floor space and reduce project costs in engineering construction has become a new direction for the development of engineering design. However, my country's embankment embankments are still facing various problems.

[0003] The sources of fillers for high embankments are complex, and the particle sizes vary. In addition, the embankment filling range is wide, making it difficult to ensure the compaction and uniformity of the high embankment. Under the action of live loads, the fill particles of ordinary embankments creep and deform, which is prone to uneven settlement after construction, local settlement, uneven damage to the road base, and cracking of the road surface; it is difficult to match particles of the same thickness during construction, and it is difficult and costly to reduce large particles. The overlapping of small particles forms a loose structure that is not conducive to the stability of the embankment; vibration rolling can easily make the fill The filler at the edge of the embankment slope is loose and sprayed out, which increases the cost of repair and is prone to compaction hazards; the high embankment designed according to general fill and slope design occupies a wider area, and in some areas with expensive land prices or concentrated residents, it is necessary to increase land acquisition and demolition fees. In areas with restricted terrain, it may be difficult to slope, and retaining structures have to be added, thereby increasing the project cost; secondly, in the plain high-yield farmland area, not only does the embankment itself occupy a large amount of basic farmland, but also the basic farmland has to be temporarily occupied due to the shortage of filler and soil, resulting in a waste of resources.

[0004] The invention patent with publication number CN108166524A discloses an engineering method for managing large-scale, high fill slopes and its thin-walled box retaining wall. Although the thin-walled box retaining wall in the invention patent combines the technical features of cantilever (supporting) arm retaining walls and gravity retaining walls and can reinforce the slopes, it still has the disadvantages of cumbersome procedures, complex construction and high engineering cost.

[0005] The invention patent with publication number CN110258220A discloses a method for ecologically constructing road embankments with high-strength steel wire mesh reinforced materials. The invention patent uses high-strength steel wire mesh to integrally reinforce the embankment. Although it can improve the overall shear strength of the embankment slope, the embankment under the road is only subjected to the pressure of the upper load. Reinforcing this part of the embankment will cause waste of materials and increase the project cost.

[0006] The existing high and steep embankment slope reinforcement methods generally have the following problems:

[0007] (1) The existing high and steep embankments have complex fill sources and uneven particle sizes. At the same time, the embankment filling area is large, making it difficult to ensure uniform compaction, which leads to embankment diseases such as uneven settlement and slope sliding deformation after construction;

[0008] (2) Traditionally, steep embankment slopes are usually stabilized by slope reduction. However, in some areas with high land prices, concentrated populations, and high-yield farmland, this will increase land acquisition and demolition costs, waste resources, and increase project costs.

[0009] (3) Traditional embankment filling and support technology reinforces the embankment as a whole, without making rational use of the stress characteristics of the embankment and considering zone reinforcement. The reinforcement effect does not reach the optimal state, and it will also cause waste of resources and increase project costs. Summary of the invention

[0010] In order to solve the above problems, the present invention provides a three-dimensional zoning structure of a high and steep embankment, which is divided into a deformation control area and a shear control area according to the stress characteristics of the embankment. The shear control area is reinforced in stages, which reduces the settlement and deformation of the embankment during use, effectively reduces the occupation of farmland and house demolition, reduces engineering costs, and solves the problems existing in the prior art.

[0011] Another object of the present invention is to provide a construction method for a three-dimensional partition structure of a high and steep embankment.

[0012] The technical solution adopted by the present invention is a three-dimensional partition structure of a high and steep embankment, including an embankment partition structure, an anchoring system and a drainage system;

[0013] The embankment zoning structure is divided into a deformation control zone and a shear control zone. The shear control zone is located in the range from the embankment slope surface to 2 to 5 meters inside the embankment, and the rest is the deformation control zone; the shear control zone is divided into multiple levels vertically, and the cement content of the cement-modified soil used in each level of the shear control zone decreases from bottom to top. The shear control zone is obtained by layered filling and compaction of cement-modified soil with different cement contents and geogrids; the deformation control zone is obtained by layered filling and compaction of plain fill soil;

[0014] The anchoring system includes a gabion structure on the embankment slope to reinforce and protect the soil in the shear control area;

[0015] The drainage system includes slope platform drainage ditches, slope bottom drainage ditches and longitudinal drainage ditches.

[0016] Furthermore, the gabion structure comprises:

[0017] A waterproof geotextile, which is laid on the steps on the slope surface;

[0018] A reinforced concrete slab is arranged at the vertical surface of the step on the slope surface, close to the shear control area, and an internal geogrid is buried in the middle of the reinforced concrete slab, and the internal geogrid extends into the shear control area;

[0019] The gabion steel mesh is arranged on the outside of the reinforced concrete slab and is filled with stone blocks.

[0020] Furthermore, the longitudinal drainage ditches are located on the surface of the embankment slope, are arranged at intervals along the longitudinal direction of the embankment slope, and extend from the top of the slope to the bottom of the slope.

[0021] Furthermore, the method for determining the cement content of the cement-modified soil used in each level of the shear control zone is as follows:

[0022] Determine the shear safety factor according to the actual design requirements, and calculate the cohesion and internal friction angle c of each soil layer on the side of the soil strip by inverse calculation using equations (1) to (3): i '、 The relationship between cement content, cohesion and internal friction angle is obtained through experiments, and then the cohesion and internal friction angle c of each soil layer on the side of the soil strip are obtained by inverse calculation. i '、 The corresponding cement content; if the two cement content values ​​are different, take the minimum value;

[0023]

[0024]

[0025] In the formula, E a is the active earth pressure, H is the height of the soil block, c is the cohesion of the soil, K a is the Coulomb active earth pressure coefficient; γ, is the weight and internal friction angle of the fill; α is the inclination angle between the shear control area 2 and the vertical line, with the vertical line as the standard, counterclockwise is positive and clockwise is negative; β is the inclination angle between the fill surface of the deformation control area 1 and the horizontal plane, above the horizontal plane is positive and below the horizontal plane is negative; δ is the friction angle between the fill of the shear control area 2 and the deformation control area 1, which is taken as

[0026] Simplify the soil, get the calculation diagram, and derive the formula:

[0027]

[0028] W i is the soil strip’s own gravity; α i represents the angle between the lower part of the i-th soil strip and the horizontal direction; F s is the safety factor; P iP represents the thrust transmitted from the i-th soil strip to the i+1-th soil strip, parallel to the bottom sliding surface of the i-th soil strip; i-1 represents the thrust transmitted from the i-1th soil strip to the i-th soil strip, parallel to the bottom sliding surface of the i-1th soil strip; Q i Represents the horizontal force of the soil strip; l i Indicates the length of the soil strip; u i represents the pore stress at the bottom of the soil strip; tg is the tangent function; c i '、 Represents the lateral cohesion and internal friction angle of each soil layer;

[0029] Transmission coefficient ψ i-1 Calculated by formula (2):

[0030]

[0031] P on the interface of each soil strip i After the calculation, the shear safety factor F on this interface is calculated according to formula (3): vi :

[0032]

[0033] Where: U pi represents the pore water pressure acting on the side of the soil strip; h i Indicates the side height of the soil strip.

[0034] Furthermore, the cement modified soil (3) comprises cement, composite fiber, plain fill soil and water; the weight ratio of cement to composite fiber is

[0035] Furthermore, the composite fiber is woven with spandex filaments as the core and short-cut glass fibers as the outer covering, and the weight ratio of the spandex filaments to the short-cut glass fibers is 1:1.

[0036] A construction method for a high and steep embankment three-dimensional partition structure comprises the following steps:

[0037] Step S1, laying out, excavating to the designed elevation, and leveling the base;

[0038] Step S2, filling the deformation control area with plain fill, controlling the optimal moisture content, the compaction degree is 94% to 96%, and the thickness after filling and compaction is 10 to 20 cm; filling the shear control area with cement modified soil, the compaction degree is 93%, and the cement content of different levels of cement modified soil is different; during the filling process, the surface of the embankment slope is formed into a step shape, and a slope of 1° to 3° is set on the step surface;

[0039] Step S3, repeating step S2, when the height after filling and compaction is half of the step height, laying a waterproof geotextile on the step on the slope surface, with the overlap length between the waterproof geotextiles being 20 cm to 30 cm, and the waterproof geotextiles being arranged to 1 / 3 to 2 / 3 of the step elevation height;

[0040] Step S4, hoisting the reinforced concrete slab to the designed position, laying the built-in geogrid in the reinforced concrete slab on the surface of the cement-modified soil filled in the shear control area, reserving expansion joints between two adjacent reinforced concrete slabs, and reserving the position of the longitudinal drainage ditch at a certain length in the longitudinal direction; installing the gabion steel mesh in the gabion structure, and filling the gabion steel mesh with block stones;

[0041] Step S5, when the filling reaches the designed height, the geogrid is laid in the shear control area, from the junction of the deformation control area and the shear control area to the outside of the slope; the remaining geogrids are laid longitudinally until the entire shear control area is covered with geogrids, and the overlap length between each two geogrids is not less than 0.5m;

[0042] Step S6, repeating steps S2 to S5, supporting and filling until the designed embankment height is reached, and grading is performed after the height of the filled embankment reaches a certain height, and a slope platform is reserved;

[0043] Step S7, constructing a bottom drainage ditch on each level of the embankment slope platform and at the bottom of the embankment slope, constructing a slope platform drainage ditch on each level of the embankment slope platform, and constructing a longitudinal drainage ditch at the position of the longitudinal drainage ditch reserved in step S4.

[0044] Furthermore, the width of the slope platform drainage ditch is 0.2~0.4m, the depth is 0.2~0.4m, and the longitudinal slope along the embankment is 2°~4°; the width of the longitudinal drainage ditch is 0.2~0.4m, the depth is 0.2~0.4m, extending from the top of the slope to the bottom of the slope; the width of the drainage ditch at the bottom of the slope is 0.4~0.6m, and the depth is 0.4~0.6m.

[0045] Furthermore, the geogrid is made of glass fiber, the width of a single piece is 5 to 7 meters, and the ultimate tensile strength is not less than 80 kN / m.

[0046] Furthermore, the height of the reinforced concrete slab is the height of the step on the slope surface, the width of the reinforced concrete slab is twice the width of the step on the slope surface, a lifting hole is reserved, and prestressed steel bars are arranged inside the reinforced concrete slab.

[0047] The beneficial effects of the present invention are:

[0048] (1) The three-dimensional partitioning structure of the high and steep embankment in the embodiment of the present invention is suitable for high and steep embankments. It is divided into a deformation control area and a shear control area according to the different stress characteristics of the embankment. The shear control area is graded in the vertical direction and different reinforcement measures are taken. It is suitable for high and steep slopes, reduces construction land, reduces the large cost caused by land acquisition, effectively saves land resources, and reduces construction costs.

[0049] (2) The embodiment of the present invention calculates the shear stress on each level of the area based on the calculation model, selects cement-modified soil and geogrids with different contents for reinforcement, and uses the geogrid to restrict the lateral movement of the soil to form a good interlocking effect, so that the soil has good overall shear resistance. The cement-modified soil arranged above and below the geogrid increases the overall shear resistance of the entire shear control area, reducing the risk of shallow instability of the embankment slope.

[0050] (3) The embodiment of the present invention calculates and determines the shear stress that each level of the shear control zone is subjected to when it reaches failure. By introducing a safety factor and inverting the proportion of the modifier in the cement-modified soil used at that level, the characteristics of the material can be utilized to the maximum extent, the use of anchor rods can be avoided, and the project cost can be reduced. Geogrids are relatively light, and the construction process is a process of assembly, filling, and rolling. They are suitable for both mechanized and manual construction, and the construction equipment is simple, the construction quality is easy to control, and the construction management is relatively simple.

[0051] (4) The shear control area of ​​the embodiment of the present invention provides an anchoring space for the embankment surface support structure. The support structure on the embankment slope surface reinforces the soil in the shear control area. At the same time, the anchoring system can prevent rainwater from scouring the embankment slope, thereby improving the overall stability of the high and steep embankment slope. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 It is a three-dimensional zoning diagram of a high and steep embankment according to an embodiment of the present invention.

[0054] Figure 2 It is a calculation model diagram of an embodiment of the present invention.

[0055] Figure 3 It is a simplified diagram of active earth pressure calculation in the calculation model of the embodiment of the present invention.

[0056] Figure 4 It is a simplified diagram of the residual sliding force calculation in the calculation model of the embodiment of the present invention.

[0057] Figure 5 It is a top view of the support structure diagram of the high and steep three-dimensional partitioned structure in an embodiment of the present invention.

[0058] Figure 6 It is a cross-sectional view of the support structure of the high-steep three-dimensional partition structure in an embodiment of the present invention.

[0059] Figure 7 2 is a diagram of a slope support structure in an embodiment of the present invention.

[0060] Figure 8a It is the relationship between the moisture content and the internal friction angle of the cement-modified soil in the embodiment of the present invention.

[0061] Figure 8b It is the relationship between the moisture content and cohesion of the cement-modified soil in the embodiment of the present invention.

[0062] Figure 9a It is the relationship between the cement content and the internal friction angle of the cement-modified soil in the embodiment of the present invention.

[0063] Figure 9b It is the relationship between the cement content and cohesion of the cement-modified soil in the embodiment of the present invention.

[0064] In the figure: 1. deformation control zone, 2. shear control zone, 3. cement modified soil, 4. geogrid, 5. plain fill, 6. gabion structure, 7. gabion steel mesh, 8. reinforced concrete slab, 9. block stone, 10. waterproof geotextile, 11. built-in geogrid, 12. slope platform drainage ditch, 13. slope bottom drainage ditch, 14. deformation control zone sliding surface, 15. shear control zone sliding surface, 16. slope surface sliding point, 17. junction point between deformation zone and shear zone, 18. longitudinal drainage ditch. DETAILED DESCRIPTION

[0065] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0066] Embodiment 1,

[0067] A high and steep embankment three-dimensional partition structure, such as Figure 1 , 7As shown in the figure, it includes embankment partition structure, anchoring system and drainage system. According to the different forces on the embankment under load, the embankment partition structure is divided into deformation control zone 1 and shear control zone 2. Shear control zone 2 is located in the range of 2 to 5m from the surface of the embankment slope to the inside of the embankment, because this part of the embankment undergoes shear deformation under load; if the range of shear control zone 2 is too small, the greater the difficulty of reinforcing the deformation control zone, the worse the support effect; if the range of shear control zone 2 is too large, it will cause waste of reinforcement materials.

[0068] The shear control zone 2 is divided into multiple levels vertically. The cement modified soil 3 used in each level of the shear control zone 2 has a different cement content. The shear control zone 2 is obtained by layered filling and compaction of cement modified soil 3 with different cement contents and geogrid 4; the deformation control zone 1 is obtained by layered filling and compaction of plain fill 5.

[0069] like Figure 2 As shown, in the deformation control zone 1, the active earth pressure at the intersection point 17 of the deformation zone and the shear zone is calculated by formula (1), and the calculated active earth pressure is applied to the shear control zone 2. The sliding force of the slope shear control zone 2 at the slope surface slip point 16 is calculated by formula (2). If the sliding force is greater than 0, the slope is unstable and the cement dosage of the cement-modified soil 3 needs to be increased. If the sliding force is less than 0, the slope is stable. The slope shear safety factor is calculated by formula (3). The intersection point of the shear control zone sliding surface 15 and the slope is the slope surface slip point 16. The deformation zone and shear zone intersection point 17 is located at the intersection of the shear control zone sliding surface 15 and the settlement control zone.

[0070] like Figure 3 As shown, the soil is simplified into triangle ABC, and formula (1) is derived;

[0071]

[0072]

[0073] In the formula, E a is the active earth pressure, H is the height of the soil block, c is the cohesion of the soil, K a is the Coulomb active earth pressure coefficient; γ, is the weight and internal friction angle of the fill; α is the inclination angle between the shear control area 2 and the vertical line, with the vertical line as the standard, counterclockwise is positive and clockwise is negative; β is the inclination angle between the fill surface of the deformation control area 1 and the horizontal plane, above the horizontal plane is positive and below the horizontal plane is negative; δ is the friction angle between the fill of the shear control area 2 and the deformation control area 1, and its value can be determined by experiment, and is generally taken as

[0074] like Figure 4 As shown in the figure, the soil is simplified to obtain a calculation diagram, and the following formula is derived:

[0075]

[0076] W i is the soil strip’s own gravity; α i represents the angle between the bottom of the i-th soil strip and the horizontal direction (the slope angle of the bottom of the soil strip); F s is the safety factor; P i P represents the thrust transmitted from the i-th soil strip to the i+1-th soil strip, parallel to the bottom sliding surface of the i-th soil strip; i-1 represents the thrust transmitted from the i-1th soil strip to the i-th soil strip, parallel to the bottom sliding surface of the i-1th soil strip; Q i It is expressed as the horizontal force acting on the soil strip; the length of the soil strip is l i ;u i represents the pore stress at the bottom of the soil strip; tg is the tangent function expression;

[0077] c i '、 It represents the cohesion and internal friction angle of each soil layer on the side of the soil strip. Figure 4 In, N i is the total normal reaction force at the bottom of the soil strip, T i is the total tangential resistance at the bottom of the soil strip (slip surface), U i is the pore water pressure acting on the soil strip.

[0078] In the above formula, the transmission coefficient ψ i-1 Use formula (2) to calculate:

[0079]

[0080] P on the interface of each soil strip i After the calculation, the shear safety factor F on this interface can be calculated according to formula (3): vi :

[0081]

[0082] Where: U pi —pore water pressure acting on the side of the soil strip; h i —Side height of soil strip.

[0083] The deformation control area 1 is mainly subjected to the pressure of the upper load and undergoes settlement deformation. The shear safety factor is determined according to the actual design requirements. The cohesion and internal friction angle c of each soil layer on the side of the soil strip are calculated by inverse calculation using equations (1) to (3). i '、 (shear strength index); the optimum moisture content of cement-modified soil with different cement contents is determined by experiments, such as Figure 8a-8b; The relationship between the amount of cement and composite fiber in cement-modified soil and the shear strength of the modified soil is determined by direct shear test, that is, the relationship between cement content and cohesion and internal friction angle is obtained by test, such as Figure 9a-9b ; Then obtain the cohesion and internal friction angle c of each soil layer on the side of the soil strip obtained by inversion calculation i '、 Corresponding cement content, if two cement content values ​​are different, take the minimum value, that is, the optimal content, which can both meet the strength requirements and reduce cement consumption.

[0084] The embodiment of the present invention takes the shear strength index of each level of the shear control zone 2 as the target value, and inverts the content of cement and composite fiber in the cement modified soil, which can maximize the use of the material characteristics, ensure the shear strength of the mixture, improve the slope of the embankment slope, reduce the project cost, and reduce the floor space. It is suitable for embankment construction in cities and other areas and has a wide range of applications. In addition, the above method can also be used to increase the overall height of the embankment.

[0085] like Figure 5-7 As shown, the anchoring system is a gabion structure 6 on the embankment slope: the gabion structure 6 includes a reinforced concrete slab 8, a block stone 9, an internal geogrid 11, a gabion steel mesh 7 and a waterproof geotextile 10. The waterproof geotextile 10 is laid on the steps on the surface of the slope. The reinforced concrete slab 8 is arranged at the vertical surface of the steps on the surface of the slope, close to the shear control area 2. An internal geogrid 11 is buried in the middle of the reinforced concrete slab 8, and the internal geogrid 11 extends into the inside of the shear control area 2. The outer side of the reinforced concrete slab 8 is provided with a gabion steel mesh 7, and the gabion steel mesh 7 is filled with blocks of stone 9. The anchoring system uses the internal geogrid 11 to connect with the slope, avoiding the use of anchor rods and reducing the project cost. It is located on the surface of the high and steep slope, and reinforces and protects the soil in the shear control area 2 to prevent rainwater from scouring the soil on the high and steep embankment slope.

[0086] The drainage system consists of a drainage ditch 12 on the embankment slope platform, a drainage ditch 13 at the bottom of the slope and a longitudinal drainage ditch 18. The longitudinal drainage ditch 18 is located on the surface of the embankment slope and is arranged at a certain distance along the longitudinal direction of the embankment slope, extending from the top of the slope to the bottom of the slope.

[0087] Embodiment 2,

[0088] A construction method for a high and steep embankment three-dimensional partition structure is carried out according to the following steps:

[0089] Step S1, laying out and excavating, stopping excavation when the excavator is 20-30 cm away from the designed elevation of the base, cleaning it manually to the designed elevation, and rolling it with a vibrating roller to keep the base clean and flat, and reduce the situation where debris is mixed and affects the stability of the embankment. The base is composed of cement and gravel;

[0090] Step S2, after the base construction is completed, the shear control area 2 and the deformation control area 1 are filled with soil by a loader, the loader starts to pour soil from the inlet direction and the outlet direction at the same time, and the soil is leveled by an excavator and assisted by manual leveling, and the soil is leveled forward in sequence until the filling of the layer is completed; then the soil in different areas is compacted by a roller according to different compaction degrees, and the area that cannot be compacted by the machine is compacted manually;

[0091] The soil sample used for filling in the deformation control area 1 by a loader is plain fill 5, and the optimum moisture content is achieved by sprinkling water. The thickness after filling and compaction is 15 to 20 cm, and the plain fill 5 is compacted with a compaction degree of 94% to 96%. The specification requires that the maximum compaction thickness of each layer of roadbed filling should not exceed 25 cm; if the thickness after compaction is too large, the compaction effect will be poor and the expected designed compaction degree will not be achieved; if the thickness after compaction is too small, the construction will be complicated and the construction period will be long.

[0092] The soil sample used for filling the shear control area 2 with a loader is cement modified soil 3 with different cement contents, and is compacted with a compaction degree of 93%;

[0093] The cement content in cement-modified soil 3 is determined by calculation according to formulas (1), (2) and (3);

[0094] The cement modified soil 3 includes x parts by weight of cement and The composite fiber and plain fill of 200 parts by weight are uniformly mixed by mechanical mixing; the cement content in the filler used in each shear control zone is determined by formulas (1) to (3), so that the classification method is more reasonable. The composite fiber is woven with spandex filament as the core and short glass fiber as the outer layer, and the weight ratio of spandex filament to short glass fiber is 1:1; then water is added (the amount of water added is selected according to the best water-cement ratio of the cement used, so as to determine the water content) and continued to mix until uniform; the preparation method of cement modified soil is as follows: 84.25 to 84.83 parts by weight of plain fill, 5 to 15 parts by weight of cement modified soil, 0.17 to 0.75 parts by weight of composite fiber, water is added and mixed until uniform, and the water content of cement modified soil is 18% to 20%.

[0095] When the roller rolls the filled soil sample, it adopts different compaction speeds according to the properties of the filled soil. When the rolling of one section is finished, it adopts the longitudinal retreat method to continue the second rolling. It is not advisable to use the U-turn method to avoid the soil being squeezed and squeezed when the machine turns around, and the test compacted soil is loosened. The roller always performs compaction operations in the longitudinal forward and backward manner, and adopts longitudinal divisions from both sides to the middle. The joints between the two rows should generally overlap by 1 / 4 to 1 / 3 of the wheel track. After the longitudinal sections are compacted, after the second section is compacted, the rolling range at the longitudinal joints should overlap by 1 to 2m to ensure a smooth transition at the joints;

[0096] During the filling process, the surface of the embankment slope is formed into steps, with a width of 0.5m and a height of 1m. A slope of 1° to 3° is set on the step surface to reserve a position for the installation of the gabion structure on the slope surface and facilitate drainage of the slope surface.

[0097] Step S3, repeating step S2, when the height after filling and compaction is half of the step height, i.e. 0.5m, laying a waterproof geotextile 10 on the step on the slope surface, the overlapping length between the waterproof geotextiles 10 is 20cm to 30cm, and the waterproof geotextile 10 is arranged to 1 / 3 to 2 / 3 of the step elevation height, to protect the slope surface and avoid rain erosion;

[0098] Step S4, use a crane to lift the reinforced concrete slab 8 in the gabion structure 6 on the surface of the embankment slope. After lifting to the designed position, lay the built-in geogrids 11 in the two reinforced concrete slabs 8 on the surface of the cement-modified soil 3 filled in the shear control area 2, and at the same time reserve a certain width of expansion joints between two adjacent reinforced concrete slabs 8, reserve the position of longitudinal drainage ditches 18 at regular intervals in the longitudinal direction, install the gabion steel mesh 7 in the gabion structure 6 and fill it with stone blocks 9, and then repeat step S2 for filling.

[0099] The height of the reinforced concrete slab 8 is the same as the height of the step on the slope surface, and the width of the reinforced concrete slab 8 is twice the width of the step on the slope surface. In the embodiment, the reinforced concrete slab 8 is 1m high and 1m wide, and a hoisting cavity is reserved, and prestressed steel bars are arranged inside; the built-in geogrid 11 is arranged in the middle of the reinforced concrete slab 8. A 20cm wide expansion joint is reserved between two adjacent reinforced concrete slabs 8, and a longitudinal drainage ditch 18 is reserved every 10m in the longitudinal direction.

[0100] The material of the gabion box is highly corrosion-resistant PE film + steel mesh, the mesh size is 8×10cm, the mesh wire diameter is 2.5mm, the plastic-coated edge wire diameter is 3.5mm, and the diameter after plastic coating is 4.5mm; the diameter of the stone blocks 9 filled in the box is between 20 and 30cm.

[0101] Step S5, when the filling reaches a certain height (1m), a single geogrid 4 is laid in the shear control area 2, from the inner side of the filling (the junction of the deformation control area 1 and the shear control area 2) to the outer side, and the rest is rolled up and placed on the outer side of the filling embankment; the laid geogrid 4 is spaced uniformly with the pre-buried geogrid 4 in the slope surface support structure, and the layout is uniform; the width of a single geogrid 4 is 5 to 7m, and the ultimate tensile strength is not less than 80kN / m; the remaining single geogrids 4 are laid longitudinally until the entire shear control area 2 is covered with geogrids 4, and the overlap length between each two geogrids 4 is ensured to be not less than 0.5m. The geogrid 4 plays the role of reinforcing the shear control area 2 and improving the shear strength of the entire shear control area.

[0102] Step S6, repeating steps S2 to S5; filling while supporting until the designed embankment height is reached, and grading is performed after the height of the filled embankment reaches a certain height, and a slope platform of a certain width is reserved; and then filling is performed according to the designed embankment width until the designed embankment height is reached;

[0103] Step S7, constructing a bottom drainage ditch 13 on each level of the embankment slope platform and at the bottom of the embankment slope; constructing a slope platform drainage ditch 12 on each level of the embankment slope platform, the slope platform drainage ditch 12 has a width of 0.2-0.4m and a depth of 0.2-0.4m, and a longitudinal slope of 2°-4° along the embankment; constructing a longitudinal drainage ditch 18 at the position of the longitudinal drainage ditch 18 reserved in step S4, the longitudinal drainage ditch 18 has a width of 0.2-0.4m and a depth of 0.2-0.4m, extending from the top of the slope to the bottom of the slope; constructing a bottom drainage ditch 13 with a width of 0.4-0.6m and a depth of 0.4-0.6m at the bottom of the embankment slope.

[0104] The three-dimensional partition structure of the high and steep embankment of the embodiment of the present invention partitions the embankment in three-dimensional space according to the stress characteristics, and grades it in the vertical direction. Different reinforcement measures are adopted according to the different stress characteristics of each area. For example, the deformation control area 1 is mainly subjected to the pressure of the upper load of the embankment and thus deforms. The deformation of the embankment deformation control area 1 is mainly reduced by increasing the compaction degree; the shear control area 2 is mainly subjected to shearing, and the shear force required for the destruction of each level of the shear control area 2 is different (gradually decreasing from bottom to top), and the shear control area 2 is vertically graded; by calculating more accurately inverting the proportion of cement in the cement-modified soil 3 used in this level, cement-modified soil 3 is used for slope reinforcement, which can effectively prevent uneven settlement, slope sliding and other diseases that occur during the use of the project, ensure that the embankment shear control area 2 reaches a more stable boundary, can build a high and steep embankment, and reduce land use; steepening the slope and making it vertical can reduce construction land. The embankment applicable to the embodiment of the present invention is a high and steep embankment with a height greater than 20m and a slope of 3% to 10%.

[0105] The existing cement usage is 25% to 30%, and the cement usage in the embodiment of the present invention is 13% to 15%, which reduces the cement usage by 10% to 17%. The cement usage in the embodiment of the present invention is gradually reduced in vertical grading (from bottom to top), which maximizes the use of material properties, greatly reduces material waste, reduces cement usage, avoids the use of anchor rods, and reduces project costs.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A three-dimensional partition structure of a high and steep embankment, characterized in that: Including embankment partition structure, anchoring system and drainage system; The embankment partition structure is divided into a deformation control zone (1) and a shear control zone (2), wherein the shear control zone (2) is located in the range of 2 to 5 m from the surface of the embankment slope to the inside of the embankment, and the rest is the deformation control zone (1); the shear control zone (2) is divided into multiple levels vertically, and the cement content of the cement-modified soil (3) used in each level of the shear control zone (2) decreases from bottom to top, and the shear control zone (2) is obtained by layered filling and compaction of cement-modified soil (3) with different cement contents and geogrids (4); the deformation control zone (1) is obtained by layered filling and compaction of plain fill (5); The anchoring system includes a gabion structure (6) on the embankment slope surface, which reinforces and protects the soil in the shear control area (2); The drainage system comprises a slope platform drainage ditch (12), a slope bottom drainage ditch (13) and a longitudinal drainage ditch (18); Determination of cement content of cement-modified soil (3) used in each level of the shear control zone (2): Determine the shear safety factor according to the actual design requirements, and calculate the cohesion and internal friction angle c of each soil layer on the side of the soil strip by inverse calculation using equations (1) to (3): i '、 The relationship between cement content, cohesion and internal friction angle is obtained through experiments, and then the cohesion and internal friction angle c of each soil layer on the side of the soil strip are obtained by inverse calculation. i '、 The corresponding cement content; if the two cement content values ​​are different, take the minimum value; In the formula, E a is the active earth pressure, H is the height of the soil block, c is the cohesion of the soil, K a is the Coulomb active earth pressure coefficient; γ, is the weight and internal friction angle of the fill; α is the inclination angle between the shear control area (2) and the vertical line, with the vertical line as the reference, counterclockwise is positive and clockwise is negative; β is the inclination angle between the fill surface of the deformation control area (1) and the horizontal plane, above the horizontal plane is positive and below the horizontal plane is negative; δ is the friction angle between the fill in the shear control area (2) and the deformation control area (1), which is taken as Simplify the soil, get the calculation diagram, and derive the formula: W i is the soil strip’s own gravity; α i represents the angle between the lower part of the i-th soil strip and the horizontal direction; F s is the safety factor; P i P represents the thrust transmitted from the i-th soil strip to the i+1-th soil strip, parallel to the bottom sliding surface of the i-th soil strip; i-1 represents the thrust transmitted from the i-1th soil strip to the i-th soil strip, parallel to the bottom sliding surface of the i-1th soil strip; Q i Represents the horizontal force of the soil strip; l i Indicates the length of the soil strip; u i represents the pore stress at the bottom of the soil strip; tg is the tangent function; c i '、 Represents the lateral cohesion and internal friction angle of each soil layer; Transmission coefficient ψ i-1 Calculated by formula (2): P on the interface of each soil strip i After the calculation, the shear safety factor F on this interface is calculated according to formula (3): vi : Where: U pi represents the pore water pressure acting on the side of the soil strip; h i Indicates the side height of the soil strip.

2. A three-dimensional partition structure of a high and steep embankment according to claim 1, characterized in that: The gabion structure (6) comprises: A waterproof geotextile (10), wherein the waterproof geotextile (10) is laid on a step on the surface of the slope; A reinforced concrete slab (8), the reinforced concrete slab (8) being arranged at the vertical surface of the step on the slope surface, close to the shear control zone (2), an internal geogrid (11) being buried in the middle of the reinforced concrete slab (8), and the internal geogrid (11) extending into the interior of the shear control zone (2); A gabion steel mesh (7) is arranged on the outside of a reinforced concrete slab (8), and blocks of stone (9) are filled in the gabion steel mesh (7).

3. A high and steep embankment three-dimensional partition structure according to claim 1, characterized in that: The longitudinal drainage ditches (18) are located on the surface of the embankment slope, are arranged at intervals along the longitudinal direction of the embankment slope, and extend from the top of the slope to the bottom of the slope.

4. A three-dimensional partition structure of a high and steep embankment according to claim 1, characterized in that: The cement modified soil (3) comprises cement, composite fiber, plain fill soil and water; the weight ratio of cement to composite fiber is 5. A high and steep embankment three-dimensional partition structure according to claim 4, characterized in that: The composite fiber is woven with spandex filaments as the core and short-cut glass fibers as the outer covering, and the weight ratio of the spandex filaments to the short-cut glass fibers is 1:

1.

6. A construction method for a high and steep embankment three-dimensional partition structure as claimed in claim 1, characterized in that: The following steps are involved: Step S1, laying out, excavating to the designed elevation, and leveling the base; Step S2, filling the deformation control area (1) with plain fill (5), controlling the optimum moisture content, the compaction degree of 94% to 96%, and the thickness after filling and compaction of 10 to 20 cm; filling the shear control area (2) with cement modified soil (3), the compaction degree of 93%, and different levels of cement modified soil (3) having different cement contents; during the filling process, the surface of the embankment slope is formed into a step shape, and a slope of 1° to 3° is set on the step surface; Step S3, repeating step S2, when the height after filling and compaction is half the height of the step, laying a waterproof geotextile (10) on the step on the slope surface, with the overlapping length between the waterproof geotextiles (10) being 20 cm to 30 cm, and at the same time, the waterproof geotextiles (10) are arranged to 1 / 3 to 2 / 3 of the height of the step elevation; Step S4, hoisting the reinforced concrete slab (8) to the designed position, laying the built-in geogrid (11) in the reinforced concrete slab (8) on the surface of the cement-modified soil (3) filled in the shear control area (2), reserving expansion joints between two adjacent reinforced concrete slabs (8), and reserving the positions of longitudinal drainage ditches (18) at regular intervals in the longitudinal direction; installing the gabion steel mesh (7) in the gabion structure (6), and filling the gabion steel mesh (7) with blocks of stone (9); Step S5, when the filling reaches the designed height, the geogrid (4) is laid in the shear control area (2), from the junction of the deformation control area (1) and the shear control area (2) to the outside of the slope; the remaining geogrids (4) are laid longitudinally until the entire shear control area (2) is covered with the geogrids (4), and the overlap length between each two geogrids (4) is not less than 0.5m; Step S6, repeating steps S2 to S5, supporting and filling until the designed embankment height is reached, and grading is performed after the height of the filled embankment reaches a certain height, and a slope platform is reserved; Step S7, construct a bottom drainage ditch (13) on each level of the embankment slope platform and at the bottom of the embankment slope, construct a slope platform drainage ditch (12) on each level of the embankment slope platform, and construct a longitudinal drainage ditch (18) at the position of the longitudinal drainage ditch (18) reserved in step S4.

7. The construction method of a high and steep embankment three-dimensional partition structure according to claim 6, characterized in that: The width of the slope platform drainage ditch (12) is 0.2-0.4 m, the depth is 0.2-0.4 m, and the longitudinal slope along the embankment is 2°-4°; the width of the longitudinal drainage ditch (18) is 0.2-0.4 m, the depth is 0.2-0.4 m, and it extends from the top of the slope to the bottom of the slope; the width of the drainage ditch (13) at the bottom of the slope is 0.4-0.6 m, and the depth is 0.4-0.6 m.

8. The construction method of a high and steep embankment three-dimensional partition structure according to claim 6, characterized in that: The geogrid (4) is made of glass fiber, with a single piece width of 5 to 7 m and an ultimate tensile strength of not less than 80 kN / m.

9. The construction method of a high and steep embankment three-dimensional partition structure according to claim 6, characterized in that: The height of the reinforced concrete slab (8) is the height of the step on the slope surface, the width of the reinforced concrete slab (8) is twice the width of the step on the slope surface, a lifting hole is reserved, and prestressed steel bars are arranged inside the reinforced concrete slab (8).

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