A design method for unit-type anti-slide retaining wall on fill slope

Abstract

The present invention relates to a design method for a unit-type anti-sliding retaining wall for a fill slope, which divides the slope into anti-sliding units by using a composite structure of tension-anchor-spacer-row. Tie rods pass through the fill area to pull the vertical retaining wall against the conical pull-out piers in the original soil. The vertical retaining wall, tie rods, and connecting beams form a unit-type closed structure to transmit the clamping force, and the conical pull-out piers balance the downward force of the inverted trapezoidal fill soil. A layer of drainage board and reinforced waterproof layer are arranged under each tie rod in the vertical direction downward, and the drainage board is connected to the drainage ditch outside the retaining wall by a through-wall drainage pipe. The beneficial effects of the present invention are as follows: the drainage board and the external drainage form a three-dimensional drainage system, which can solve the problem that conventional slope retaining wall structures only have drainage pipes on the surface and cannot solve the problem of deep drainage in the fill area; the vertical retaining wall, tie rods, and connecting beams form a unit-type closed structure to transmit the clamping force, and the conical pull-out piers balance the downward force of the inverted trapezoidal fill unit soil, which can improve the anti-overturning ability of the fill high slope and the anti-sliding wall.

Description

Technical Field

[0001] The invention relates to the technical field of construction and traffic engineering, and in particular to a design method for a fill slope unit type anti-slide retaining wall. Background Art

[0002] The reasons for large-scale landslides on high fill slopes are, on the one hand, due to the large-scale slope cutting and filling, which makes the artificial slope steeper or even vertical, greatly increasing the risk of slope instability at the toe. On the other hand, uneven settlement after the construction of the large-scale fill foundation causes cracks on the fill area. Heavy rain causes severe surface water accumulation and erosion, which flows into the cracks, washing away sediment, forming gullies that gradually expand. The infiltration increases the water pressure in the soil, reduces the soil's shear strength, and causes large-scale landslides and collapses. In addition to the triggering factor of heavy rain, the design focuses on surface drainage, while ignoring the infiltration of accumulated water and the drainage of the deep soil in the fill area, which also causes landslides.

[0003] Vertical retaining walls fill high slopes, more effectively than slope-retaining walls, effectively improving construction site utilization. Common support methods include pile-anchor support, gravity masonry retaining walls, large-diameter anti-slide piles, and buttress retaining walls. Drainage methods often rely on surface drainage to remove surface water, while deep drainage is often overlooked. Therefore, layered water separation, deep drainage, and the rational design of anti-slide structures are key considerations based on landslide principles and are important measures to reduce landslide risks, worthy of further exploration. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art. According to the instability mechanism of fill slope landslide, which is caused by the infiltration of surface water and groundwater, which washes away the sediment and reduces the shear strength of the fill foundation, a design method for a unit anti-sliding retaining wall for fill slope is provided, including adopting a tension-anchor-partition-row composite structure to form an anti-sliding system, using tension rods to pull the upright retaining wall and the cone-shaped anti-pullout pier in the original soil, laying a layer of waterproof membrane + wire mesh + waterproof membrane sandwich structure reinforced waterproof layer under each vertical tension rod, laying drainage boards on the reinforced waterproof layer at intervals, and the drainage boards pass through the retaining wall to connect the wall drainage groove. The wall drainage groove and the planting groove are a double-layer structure, and the middle partition has water-permeable holes. It can solve the problem that conventional slope retaining wall structures only have drainage pipes on the surface and cannot solve the deep drainage of the fill area. It can improve the anti-overturning ability of high fill slopes and anti-sliding walls, reduce the risk of shallow and deep landslides, and ensure the stability of high slopes in extreme rainstorm weather.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A method for designing a unit-type anti-sliding retaining wall for a fill slope comprises the following steps:

[0007] S1. Determine the design parameters of the vertical retaining wall structure and fill slope, and verify that the anti-sliding stability and safety of the fill slope unit anti-sliding retaining wall meet the design requirements.

[0008] S2. Remove the vegetation layer and root soil at the interface between the fill and the original soil, replace the soft soil layer at the base of the slope with a block stone replacement layer, set up a bottom drainage ditch at the foot of the slope outside the retaining wall construction location, bury a base drainage pipe at the bottom of the block stone replacement layer, and connect the base drainage pipe to the bottom drainage ditch.

[0009] S3. Backfill soil in layers starting from the block stone replacement layer in the backfill area. The thickness of each layer should not exceed 500mm. Use rolling equipment to repeatedly vibrate and compact it. Then backfill soil and cast vertical retaining walls layer by layer. The height of the vertical retaining walls cast in sections should be equal to the vertical spacing of the connecting beams.

[0010] S4. When the fill height reaches the construction position of the cone-shaped pull-out pier, the cone-shaped pull-out pier is constructed on the original soil slope. The bottom of the cone-shaped pull-out pier passes through the potential sliding surface and is embedded in the hard original soil or rock layer. The head of the cone-shaped pull-out pier is connected into a whole with a connecting beam and welded to the tie rod through anchor bars. The length of the cone-shaped pull-out pier should meet the pull-out force requirements.

[0011] Furthermore, the length of the cone pull-out pier is determined through a pull-out test.

[0012] S5. When constructing the conical pull-out piers and connecting beams, the steel cage and supporting formwork of the vertical retaining wall shall be tied simultaneously, and the support frame and through-wall drainage pipe of the wall drainage trough shall be embedded in advance. A reinforced waterproof layer with a sandwich structure shall be laid on the earthwork at the elevation of the connecting beam.

[0013] S6. Lay a drainage board wrapped with 1-2 layers of dense nylon mesh on top of the reinforced waterproof layer, embed a tie rod above the drainage board, anchor one end of the tie rod to the main reinforcement of the retaining wall of the vertical retaining wall, and connect the other end to the anchor bar embedded in the conical pull-out pier and the connecting beam, and pour the vertical retaining wall concrete.

[0014] S7. Construct wall drainage gutters and planting troughs, and install the wall drainage gutters and planting troughs on the vertical retaining wall.

[0015] S8. Repeat steps S3-S7 until the soil is backfilled to the top of the slope and the site concrete protective surface layer is poured or the highway roadbed is constructed.

[0016] S9. An intercepting ditch is set on the inner side of the top surface of the high slope of the vertical retaining wall, and a top drainage ditch is set on the outer side of the top surface of the high slope of the vertical retaining wall. The intercepting ditch, top drainage ditch, bottom drainage ditch, drainage board and wall drainage groove together constitute a three-dimensional drainage system for the fill slope.

[0017] Furthermore, when verifying the anti-sliding stability and safety of the fill slope unit anti-sliding retaining wall, the specific verification includes: verifying the anti-sliding stability of the fill layer unit. Take the fill height and unit width between each wall drainage groove along the fill area as the load-bearing body calculation unit, and use the formula Calculate the anti-sliding stability of the i-th layer fill unit; where, is the anti-sliding safety factor of the i-th fill unit; is the characteristic value of the total foundation reaction force of the i-th fill unit, in kN; The total horizontal anti-sliding force characteristic value provided by the reinforced aquiclude and drainage board of the i-th fill unit, in kN; is the characteristic value of the total anti-sliding force at the interface between fill and undisturbed soil of the i-th fill unit, in kN; is the characteristic value of the pull-out force of a single cone-shaped pull-out pier in the i-th fill unit, in kN; is the self-weight of the i-th layer of fill unit, in kN; n is the number of cone-shaped anti-lift piers arranged per unit width in the horizontal direction of the fill area; is the top width of the i-th fill unit, in m; is the bottom width of the i-th layer of fill unit, in m; α is the inclination angle of the cone-shaped anti-lift pier; β is the inclination angle of the interface between the fill and the original soil.

[0018] Furthermore, the self-weight of the i-th layer of fill unit Calculate as follows:

[0019] , where is the density of the fill, in kN / m 3 .

[0020] Furthermore, the total anti-sliding force characteristic value of the interface between the fill and the original soil of the i-th fill unit is Calculate as follows:

[0021] , where is the anti-sliding force of the interface between fill and undisturbed soil of the i-th fill unit, in kN / m 2 ; is the height of the i-th fill unit, in m;

[0022] Furthermore, the total foundation reaction characteristic value of the i-th layer fill unit is Calculate as follows:

[0023] , where is the characteristic value of the foundation reaction force per unit area of ​​the i-th layer of fill unit, in kN / m 2 .

[0024] Furthermore, the total horizontal anti-sliding force characteristic value provided by the reinforced waterproof layer and drainage board of the i-th fill unit is Calculate as follows:

[0025] , where The total horizontal anti-sliding force characteristic value per unit area provided by the reinforced aquiclude and drainage board of the i-th fill unit, in kN / m 2 .

[0026] Furthermore, the characteristic value of the pull-out force of a single cone-shaped pull-out pier in the i-th fill unit is Determined by pull-out test.

[0027] Furthermore, the drainage board of the i-th fill unit drains all the accumulated water, so that the soil strength of the fill unit does not decrease. The sandwich structure waterproof layer isolates the accumulated water in the upper soil layer and prevents it from penetrating into the next layer of fill unit, thereby maintaining the anti-sliding safety factor of the upright retaining wall.

[0028] Furthermore, the safety of the fill layer unit is verified. The foundation bearing capacity safety factor of the i-th fill unit is , safety factor of foundation bearing capacity of the i-th fill unit Calculate as follows: .

[0029] Furthermore, a row of tie rods are laid at intervals on the drainage board, and the tie rods are inserted into the casing. The tie rods are subjected to stress, while the casing is not subjected to stress. The casing is filled with asphalt. The tie rods are made of ribbed hot-rolled steel bars with a diameter of 25mm-40mm. The tie rods can be selected for single or double use according to needs. The casing diameter is 50mm-100mm. The horizontal and vertical spacing of the tie rods are consistent with those of the cone pull-out piers. The horizontal spacing of the tie rods is 2m-4m, and the vertical spacing of the tie rods is 3m-5m. The casing is filled with asphalt to prevent the tie rods from rusting.

[0030] Furthermore, the upright retaining wall, tie rods and connecting beams form a frame-type closed structure to transmit the hoop force to the fill, and the conical pull-out piers balance the downward force of the inverted trapezoidal fill.

[0031] Furthermore, the vertical retaining wall clamping force transmitted by the tie rod is arranged in units, and the downward force of the inverted trapezoidal fill soil is balanced by the conical pull-out pier. One end of the tie rod is bent and anchored in the vertical retaining wall, and the other end is welded to the conical pull-out pier through the anchor bar; the sleeve is not anchored to the vertical retaining wall and the connecting beam.

[0032] Furthermore, the wall drainage trough and the planting trough are a double-layer structure made of cast-in-place concrete or welded steel plates. The planting trough is located above the wall drainage trough. The water outlet of the wall drainage trough is provided with a water retaining plate not less than 10 mm high to maintain 10 mm high water accumulation in the wall drainage trough. A partition is provided at the bottom of the planting trough, and a water permeable hole is provided on the partition. The partition is rectangular and laid along the planting trough. The wall drainage trough can be cleaned by removing the partition. Planting soil for planting flowers, plants or vines is laid in the planting trough. The roots of flowers, plants or vines absorb water through the water permeable holes and do not require watering or sprinkler maintenance.

[0033] Furthermore, the reinforced waterproof layer includes a waterproof membrane and a steel mesh. The waterproof membrane is provided with two layers, and the steel mesh is sandwiched between the two layers of waterproof membrane. The reinforced waterproof layer is provided with a drainage slope of not less than 0.3% from the inside to the outside to prevent the accumulated water in the upper fill from infiltrating into the lower layer.

[0034] Furthermore, the wire mesh plays a role in horizontal reinforcement of the fill layer, thereby improving the tensile strength and shear strength of the soil. The diameter of the wire mesh is 1mm-3mm, and the mesh spacing of the wire mesh is 50mm-100mm.

[0035] Furthermore, the drainage board consists of an upper permeable board, a lower board and a reinforced mesh board. The reinforced mesh board is arranged in one direction perpendicular to the vertical retaining wall. The mesh diameter of the upper permeable board and the reinforced mesh board is 2mm-3mm, and the mesh spacing is 10mm-20mm; the top and sides of the drainage board are wrapped with 1-2 layers of dense nylon mesh to filter mud and sand; the drainage board is directly placed on the reinforced waterproof layer, maintaining a drainage slope of not less than 0.3%. One end of the drainage board is inserted into the original soil combined slope, and the other end is connected to the through-wall drainage pipe.

[0036] Furthermore, the angle between the cone surface of the cone-shaped anti-pullout pier and the axis is 15°-30°.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The present invention sets up multiple sandwich-structured waterproof layers consisting of waterproof membrane + wire mesh + waterproof membrane in the vertical high slope fill area, so that rainwater that infiltrates from the surface into the ground is isolated in layers and drained away by drainage boards, which will not cause underground water accumulation and reduce the shear strength of the soil, and improve the ability to resist uneven settlement caused by the upper fill.

[0039] 2. The vertical high-slope fill area of ​​the present invention is connected to the retaining wall and conical pullout piers via tie rods. The vertical retaining wall, tie rods, and connecting beams form a frame-like closed structure that transmits the clamping force to balance the downward force of the inverted trapezoidal fill. The tie rod sleeves are filled with asphalt to make the tie rods waterproof and rust-proof, improving their durability. The sleeves are not subjected to stress, ensuring equal tension at both ends of the tie rods and eliminating the need for high-strength materials.

[0040] 3. The wall drainage trough and planting trough of the present invention are double-layer structures of cast-in-place concrete or welded steel plates. The bottom partition of the planting trough has water-permeable holes. The roots of flowers, plants or creepers in the planting trough pass through the water-permeable holes to absorb water in the drainage trough, and no manual or sprinkler watering or maintenance is required.

[0041] 4. At the base of the vertical high slope fill area, block stone is used to replace the fill layer to drain the groundwater at the bottom of the fill area and deep soil, improve the bearing capacity of the foundation of the fill area, and maintain the stability of the high slope.

[0042] 5. The present invention adopts the anti-sliding safety factor of the fill area layered unit and the safety factor of the foundation bearing capacity of the layered unit method to calculate the slope stability. Compared with the commonly used arc sliding method and numerical analysis method, the force is clear and the calculation method is simple and clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the first cross section of the earth fill slope unit type anti-slide retaining wall in the present invention;

[0044] Figure 2 Schematic diagram of the second cross section of the earth fill slope unit type anti-slide retaining wall in the present invention;

[0045] Figure 3 for Figure 1 A schematic diagram of the structure enlargement at point A;

[0046] Figure 4 for Figure 1 A magnified schematic diagram of the structure at point B in FIG;

[0047] Figure 5 for Figure 2 A magnified schematic diagram of the structure at position C in FIG;

[0048] Figure 6 for Figure 2 A magnified schematic diagram of the structure at D in FIG.

[0049] Figure 7 Schematic diagram of the cross-sectional structure of the pull rod in the present invention;

[0050] Figure 8 Schematic diagram of the planar structure of the partition in the present invention;

[0051] Figure 9 It is a three-dimensional schematic diagram of the drainage board structure in the present invention;

[0052] Figure 10 This is a schematic diagram of slope stability calculation and analysis in the present invention.

[0053] In the figure: 1. Vertical retaining wall; 101. Interface between fill and original soil; 102. Wall drainage trough; 103. Main reinforcement of retaining wall; 2. Conical pull-out pier; 201. Connecting beam; 202. Anchor bar; 203. Main reinforcement of conical pull-out pier; 3. Tie rod; 301. Casing; 302. Asphalt; 4. Waterproof membrane; 401. Wire mesh; 501. Intercepting ditch; 502. Top drainage ditch; 503. Bottom drainage ditch; 6. Drainage board; 601. Close-mesh nylon mesh; 602. Earthwork; 603. Through-wall drainage pipe; 604. Upper permeable board; 605. Lower board; 606. Reinforced mesh board; 7. Stone replacement layer; 701. Base drainage pipe; 8. Planting trough; 801. Planting soil; 802. Flowers and plants; 803. Partition; 804. Permeable hole. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0055] A design method for a unit-type anti-slip retaining wall for a fill slope adopts a tension-anchor-spacer-row composite anti-slip structure to form an anti-slip system. Specifically, a tension rod 3 is used to pull the upright retaining wall 1 against the conical pull-out pier 2 in the original soil, and then a reinforced waterproof layer is laid at the elevation of each conical pull-out pier head in the vertical direction. Drainage boards 6 are then laid on the reinforced waterproof layer at intervals, and the drainage boards 6 are inserted into the wall drainage groove 102 on the upright retaining wall 1. The drainage boards pass through the retaining wall and connect to the wall drainage groove 102. The wall drainage groove and the planting groove 8 are a double-layer structure. The middle partition 803 has a water-permeable hole 804. The internal and external drainage structures form a three-dimensional drainage system.

[0056] The specific construction of the fill slope unit anti-slide retaining wall includes the following steps:

[0057] S1, such as Figure 10 As shown, the structure of the vertical retaining wall 1 and the design parameters of the fill slope are determined, and the anti-sliding stability and safety of the fill slope unit anti-sliding retaining wall meet the design requirements.

[0058] S2, such as Figure 1 、 Figure 2 As shown, the vegetation layer and root soil at the interface 101 between the fill and the original soil are excavated, and the soft soil layer at the base of the slope is replaced with a block stone replacement layer 7. A bottom drainage ditch 503 is set at the foot of the slope outside the retaining wall construction position, and a base drainage pipe 701 is buried at the bottom surface of the block stone replacement layer 7, and the base drainage pipe 701 is connected to the bottom drainage ditch 503.

[0059] S3, such as Figure 1 、 Figure 2As shown, the earth 602 is backfilled in layers starting from the block stone replacement layer 7 in the backfill area. The thickness of each layer of backfill does not exceed 500 mm, and it is repeatedly vibrated and compacted with a rolling equipment. Then, the earth is backfilled and the vertical retaining wall 1 is cast layer by layer. The height of the vertical retaining wall 1 cast in sections is equal to the vertical spacing of the connecting beam 201.

[0060] S4, such as Figure 1 As shown, when the fill reaches the construction position for the conical pier 2, the pier is constructed on the original soil slope. The main reinforcement bars 203 are embedded in the pier. The bottom of the pier passes through the potential slip surface and is embedded in the hard, original soil or rock layer. The angle between the conical surface of the pier and the axis is 15°-30°. The pier's head is connected to the pier by a connecting beam 201 and welded to the tie rod 3 via anchor bars 202. The pier's length should meet the required pullout resistance.

[0061] Specifically, the length of the cone pull-out pier is determined through a pull-out test.

[0062] S5, such as Figure 1 、 Figure 5 As shown, when constructing the conical pull-out piers and connecting beams, the steel cage and supporting formwork of the upright retaining wall 1 are tied synchronously, and the support frame and through-wall drainage pipe 603 of the wall drainage trough 102 are pre-embedded, and a reinforced waterproof layer with a sandwich structure is laid on the earth at the elevation of the connecting beam 201.

[0063] S6, such as Figure 1 、 Figure 3-Figure 5 As shown, a drainage board 6 wrapped with one to two layers of dense nylon mesh 601 is laid above the reinforced waterproof layer. A tie rod 3 is embedded above the drainage board. One end of the tie rod 3 is bent and anchored to the main retaining wall reinforcement 103 of the vertical retaining wall 1. The other end is welded to the anchor bar 202 embedded in the tapered pull-out pier 2 and the connecting beam 201. Concrete for the vertical retaining wall 1 is then poured. The casing 301 is not anchored to the vertical retaining wall 1 or the connecting beam 201.

[0064] S7, such as Figure 1 、 Figure 3 As shown, a wall drainage trough 102 and a planting trough 8 are constructed, and the wall drainage trough (102) and the planting trough (8) are installed on the vertical retaining wall (1).

[0065] S8, such as Figure 1 As shown, steps S3-S7 are repeated until the soil is backfilled to the top of the slope, and the site concrete protective surface layer is poured or the highway roadbed is constructed.

[0066] S9, such as Figure 1 、 Figure 2 、 Figure 6As shown, an intercepting ditch 501 is provided on the inner side of the top surface of the high slope of the vertical retaining wall, and a top drainage ditch 502 is provided on the outer side of the top surface of the high slope of the vertical retaining wall. The intercepting ditch 501, the top drainage ditch 502, the bottom drainage ditch 503, the drainage board 6 and the wall drainage groove 102 together constitute a three-dimensional drainage system for the fill slope.

[0067] The present invention provides a design method for a unit-type anti-sliding retaining wall for a fill slope. Based on the mechanism of fill slope landslide instability caused by the infiltration of surface water and groundwater, which washes away sediment and reduces the shear strength of the fill foundation, a pull-anchor-spacer-row composite structure is used to form an anti-sliding system. Pull rods 3 are provided in units between the vertical retaining wall 1 and the conical pull-out pier 2 to transmit the vertical retaining wall clamping force. The conical pull-out pier 2 balances the downward force of the inverted trapezoidal fill soil and protects the fill soil from being washed away by rainwater. Multiple reinforced waterproof layers composed of waterproof membrane 4, steel mesh 401, and waterproof membrane 4 are provided in the vertical high-slope fill area to isolate the accumulated water that infiltrates the ground in layers and drain it away through drainage boards, thereby maintaining the shear strength of the soil. The bottom partitions of the planting troughs 8 have permeable holes, allowing the roots of flowers, plants, or creepers in the planting troughs to absorb water from the drainage trough through the permeable holes, eliminating the need for manual or sprinkler watering and maintenance. Finally, a three-dimensional drainage system is formed by the intercepting ditch 501, the top drainage ditch 502, the bottom drainage ditch 503, the drainage board 6, and the wall drainage groove 102 to ensure the stability of the vertical fill high slope.

[0068] The use of block stone replacement layers to replace the base of the vertical high slope fill area can not only drain the groundwater in the fill area and deep soil, but also improve the bearing capacity of the foundation of the fill area and maintain the stability of the high slope.

[0069] like Figure 1 、 Figure 4 As shown, each backfill layer is repeatedly vibrated and compacted using rolling equipment, with each backfill layer thickness not exceeding 500mm. The length of the conical pullout piers 2 is determined through pullout tests to ensure they meet pullout resistance requirements. The frame-type closed structure consisting of the upright retaining wall 1, tie rods 3, and connecting beams 201 transmits a clamping force to the backfill, thereby preventing the downward trend of the inverted trapezoidal backfill.

[0070] like Figure 7 As shown, the tie rod 3 is made of ribbed hot-rolled steel bars with a diameter of 25mm-40mm. The tie rod 3 can be used alone or in pairs as needed; the outer periphery of the tie rod 3 is sleeved with a sleeve 301, the diameter of the sleeve 301 is 50mm-100mm, and the sleeve 301 is filled with asphalt 302 to prevent the tie rod 3 from rusting, thereby improving the durability of the tie rod 3.

[0071] In this embodiment, the horizontal spacing between the tie rods 3 and the horizontal spacing between the cone-shaped anti-lift piers 2 are both 2m-4m, and the vertical spacing between the tie rods 3 and the vertical spacing between the cone-shaped anti-lift piers 2 are both 3m-5m.

[0072] like Figure 6 、 Figure 8 As shown, the wall drain trough 102 and the planting trough 8 are a double-layer structure made of cast-in-place concrete or welded steel plates. The planting trough 8 is located above the wall drain trough 102. A partition 803 is provided at the bottom of the planting trough 8, and a water hole 804 is provided on the partition 803. In addition, a water retaining plate not less than 10 mm high is provided at the outlet of the wall drain trough 102 to maintain a 10 mm high level of accumulated water in the wall drain trough 102. The partition 803 is rectangular and is laid along the planting trough 8. The wall drain trough 102 can be cleaned by removing the partition 803. The planting trough 8 is paved with planting soil 801 for planting flowers and plants 802 or creepers. The roots of the flowers and plants or creepers pass through the water holes 804 to absorb moisture from the wall drain trough 102, and no watering or sprinkler irrigation is required.

[0073] like Figure 5 As shown, the reinforced waterproof layer includes a waterproof coil 4 and a steel mesh 401. When laying the reinforced waterproof layer, a layer of waterproof coil 4 is laid first, followed by a layer of steel mesh 401, and finally a layer of waterproof coil 4 is covered. The steel mesh 401 is then sandwiched between the two layers of waterproof coil 4 to form a reinforced waterproof layer with a sandwich structure. The reinforced waterproof layer is set with a drainage slope of 0.3% from the inside to the outside. The diameter of the steel mesh is 1mm-3mm, and the mesh spacing of the steel mesh is 50mm-100mm. The steel mesh 401 can horizontally reinforce the fill layer and improve the tensile strength and shear strength of the soil. By setting up the reinforced waterproof layer, rainwater that infiltrates from the surface into the ground can be isolated in layers and drained away by the drainage board 6, which will not cause underground water accumulation or reduce the shear strength of the soil, and improve the ability to resist uneven settlement caused by the upper fill.

[0074] like Figure 9 As shown, the drainage board 6 consists of an upper permeable plate 604, a lower plate 605, and a reinforced mesh plate 606. The reinforced mesh plate 606 is arranged unidirectionally, perpendicular to the vertical retaining wall 1. The mesh diameters of the upper permeable plate 604 and the reinforced mesh plate 606 are 2mm-3mm, and the mesh spacing is 10mm-20mm. The top and sides of the drainage board 6 are wrapped with one to two layers of fine-mesh nylon mesh 601 to filter sediment. The drainage board is placed directly on the reinforced aquiclude, maintaining a drainage slope of no less than 0.3%. One end of the drainage board 6 is inserted into the original soil-bonded slope, and the other end is connected to the through-wall drainage pipe 603.

[0075] like Figure 10 As shown in the figure, the present invention uses the anti-sliding safety factor of the fill area layered unit and the safety factor of the foundation bearing capacity of the layered unit to verify the anti-sliding stability and safety of the fill slope unit anti-sliding retaining wall. Compared with the commonly used arc sliding method and numerical analysis method, the force is clear and the calculation method is simple and clear. The specific verification includes the following steps:

[0076] Verify the anti-sliding stability of the fill layer unit. Figure 10 As shown in the figure, the fill height and unit width between each wall drainage groove along the fill area are taken as the load-bearing body calculation unit, according to the formula Calculate the anti-sliding stability of the i-th layer fill unit, where is the anti-sliding safety factor of the i-th fill unit, is the characteristic value of the total foundation reaction force of the i-th fill unit, in kN; The total horizontal anti-sliding force characteristic value provided by the reinforced aquiclude and drainage board of the i-th fill unit, in kN; is the characteristic value of the total anti-sliding force at the interface between fill and undisturbed soil of the i-th fill unit, in kN; is the characteristic value of the pull-out force of a single cone-shaped pull-out pier in the i-th fill unit, in kN; is the self-weight of the i-th layer of fill unit, in kN; n is the number of cone-shaped anti-lift piers arranged per unit width in the horizontal direction of the fill area; is the top width of the i-th fill unit, in m; is the bottom width of the i-th layer of fill unit, in m; α is the inclination angle of the cone-shaped anti-lift pier; β is the inclination angle of the interface between the fill and the original soil.

[0077] Specifically, the self-weight of the i-th layer of fill unit is Calculate as follows:

[0078] , where is the density of the fill, in kN / m 3 .

[0079] Specifically, the total anti-sliding force characteristic value of the interface between the fill and the original soil of the i-th fill unit is Calculate as follows:

[0080] , where is the anti-sliding force of the interface between fill and undisturbed soil of the i-th fill unit, in kN / m 2 ; is the height of the i-th fill unit, in meters.

[0081] Specifically, the total foundation reaction characteristic value of the i-th layer fill unit is Calculate as follows:

[0082] , where is the characteristic value of the foundation reaction force per unit area of ​​the i-th layer of fill unit, in kN / m 2 .

[0083] Specifically, the total horizontal anti-sliding force characteristic value provided by the reinforced aquiclude and drainage board of the i-th fill unit is Calculate as follows:

[0084] , where The total horizontal anti-sliding force characteristic value per unit area provided by the reinforced aquiclude and drainage board of the i-th fill unit, in kN / m 2 .

[0085] Specifically, the characteristic value of the pull-out force of a single cone-shaped pull-out pier in the i-th layer of fill unit is Determined by pull-out test.

[0086] Specifically, the drainage board of the i-th fill unit drains all the accumulated water, so that the soil strength of the fill unit does not decrease. The sandwich structure waterproof layer isolates the accumulated water in the upper soil layer and prevents it from penetrating into the next layer of fill unit, thereby maintaining the anti-sliding safety factor of the upright retaining wall.

[0087] Verify the safety of the fill layer unit. Figure 10 As shown, the foundation bearing capacity safety factor of the i-th layer fill unit is , safety factor of foundation bearing capacity of the i-th fill unit Calculate as follows:

[0088] .

[0089] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for designing a unit-type anti-slide retaining wall for a fill slope, characterized in that: The following steps are involved: S1. Determine the design parameters of the vertical retaining wall (1) structure and fill slope, and verify that the anti-sliding stability and safety of the fill slope unit anti-sliding retaining wall meet the design requirements; the specific verification includes: Take the fill height and unit width between each wall drainage groove (102) along the fill area as the load-bearing body calculation unit, according to the formula Calculate the anti-sliding stability of the i-th layer fill unit; where, is the anti-sliding safety factor of the i-th fill unit; is the characteristic value of the total foundation reaction force of the i-th fill unit, in kN; The total horizontal anti-sliding force characteristic value provided by the reinforced aquiclude and drainage board of the i-th fill unit, in kN; is the characteristic value of the total anti-sliding force at the interface between fill and undisturbed soil of the i-th fill unit, in kN; is the characteristic value of the pull-out force of a single cone-shaped pull-out pier in the i-th fill unit, in kN; is the self-weight of the i-th layer of fill unit, in kN; n is the number of cone-shaped anti-lift piers arranged per unit width in the horizontal direction of the fill area; is the top width of the i-th fill unit, in m; is the bottom width of the i-th layer fill unit, in m; α is the inclination angle of the cone-shaped anti-lift pier; β is the inclination angle of the interface between the fill and the original soil; S2, excavating the vegetation layer and root soil at the interface between the fill and the original soil (101), replacing the soft soil layer at the base of the slope with a block stone replacement layer (7), setting a bottom drainage ditch (503) at the foot of the slope outside the vertical retaining wall construction position, burying a base drainage pipe (701) at the bottom surface of the block stone replacement layer (7), and connecting the base drainage pipe (701) to the bottom drainage ditch (503); S3, backfilling soil (602) in layers upwards from the block stone replacement layer (7) in the backfill area, with each layer of backfill not exceeding 500 mm in thickness, and repeatedly vibrating and compacting with a rolling device, and then backfilling and casting vertical retaining walls (1) layer by layer upwards, with the height of the vertical retaining walls (1) cast in sections being equal to the vertical spacing of the connecting beams (201); S4. When the fill height reaches the construction position of the cone pull-out pier (2), the cone pull-out pier (2) is constructed on the original soil slope. The bottom end of the cone pull-out pier (2) passes through the potential sliding surface and is embedded in the hard original soil or rock layer. The head of the cone pull-out pier (2) is connected to form a whole with a connecting beam (201) and is welded to the tie rod (3) through the anchor bar (202). The length of the cone pull-out pier (2) meets the pull-out force requirement. The length of the cone pull-out pier (2) is determined by the pull-out test. The vertical retaining wall (1), the tie rod (3) and the connecting beam (201) form a frame-type closed structure to transmit the hoop force to the fill, and the cone pull-out pier (2) balances the downward force of the inverted trapezoidal fill soil. S5. When constructing the cone-shaped anti-lift pier and the connecting beam, the steel cage and the supporting formwork of the vertical retaining wall (1) are tied synchronously, and the support frame and the through-wall drainage pipe (603) of the wall drainage trough (102) are embedded in the steel cage of the vertical retaining wall (1). A reinforced waterproof layer with a sandwich structure is laid on the earth at the elevation of the connecting beam (201); the reinforced waterproof layer includes a waterproof roll (4) and a steel wire mesh (401), the waterproof roll (4) has two layers, and the steel wire mesh (401) is sandwiched between the two layers of waterproof roll (4). The reinforced waterproof layer is set with a drainage slope of not less than 0.3% from the inside to the outside to prevent the water in the upper fill from penetrating to the lower layer; the steel wire mesh (401) plays a horizontal reinforcement role on the fill layer, thereby improving the tensile strength and shear strength of the soil, and the mesh spacing of the steel wire mesh (401) is 50mm-100mm; S6. A drainage board (6) wrapped with 1-2 layers of dense nylon mesh (601) is laid on the reinforced waterproof layer, and a tie rod (3) is pre-buried on the drainage board (6). A row of tie rods (3) are laid on the drainage board (6) at intervals, and one end of the tie rod (3) is anchored to the main reinforcement (103) of the vertical retaining wall (1), and the other end is connected to the anchor bar (202) embedded in the cone pull-out pier (2) and the connecting beam (201). The vertical retaining wall (1) is poured with concrete; the drainage board (6) is composed of an upper permeable plate (604), a lower plate (605) and a reinforced The mesh plate (606) is composed of a reinforced mesh plate (606) arranged in a unidirectional manner perpendicular to the vertical retaining wall (1). The mesh diameter of the upper permeable plate (604) and the reinforced mesh plate (606) is 2mm-3mm, and the mesh spacing is 10mm-20mm. The top and side surfaces of the drainage plate (6) are wrapped with 1-2 layers of dense nylon mesh (601) to filter sediment. The drainage plate is directly placed on the reinforced waterproof layer and maintains a drainage slope of not less than 0.3%. One end of the drainage plate is inserted into the original soil combined slope surface, and the other end is connected to the through-wall drainage pipe (603); S7, constructing a wall drainage trough (102) and a planting trough (8), and installing the wall drainage trough (102) and the planting trough (8) on the vertical retaining wall (1); S8. Repeat steps S3-S7 until the soil is backfilled to the top of the slope and the site concrete protective surface layer is poured or the highway roadbed is constructed; S9. An intercepting ditch (501) is provided on the inner side of the top surface of the high slope of the vertical retaining wall, and a top drainage ditch (502) is provided on the outer side of the top surface of the high slope of the vertical retaining wall. The intercepting ditch (501), the top drainage ditch (502), the bottom drainage ditch (503), the drainage board (6) and the wall drainage groove (102) together constitute a three-dimensional drainage system for the fill slope.

2. The design method of the earth fill slope unit type anti-slide retaining wall according to claim 1 is characterized in that: The tie rod (3) is inserted into the sleeve (301), the tie rod (3) is stressed, while the sleeve (301) is not stressed. The sleeve (301) is not anchored to the vertical retaining wall (1) and the connecting beam (201). The sleeve (301) is filled with asphalt (302). The tie rod (3) is made of ribbed hot-rolled steel bars with a diameter of 25mm-40mm. The diameter of the sleeve (301) is 50mm-100mm. The horizontal spacing of the tie rod (3) and the vertical spacing of the tie rod (3) are consistent with those of the cone pull-out pier (2). The horizontal spacing of the tie rod (3) is 2m-4m, and the vertical spacing of the tie rod (3) is 3m-5m. The sleeve (301) is filled with asphalt (302) to prevent the tie rod (3) from rusting.

3. The design method of the earth fill slope unit type anti-slide retaining wall according to claim 1, characterized in that: The wall drainage trough (102) and the planting trough (8) are a double-layer structure made of cast-in-place concrete or welded steel plates. The planting trough (8) is located above the wall drainage trough (102). The water outlet of the wall drainage trough (102) is provided with a water retaining plate not less than 10 mm high to maintain 10 mm high water accumulation in the wall drainage trough (102). A partition (803) is provided at the bottom of the planting trough (8). A water permeable hole (804) is provided on the partition. The partition is rectangular and laid along the planting trough (8). The wall drainage trough (102) can be cleaned by removing the partition (803). Planting soil (801) for planting flowers and plants (802) or creepers is laid in the planting trough (8). The roots of the flowers and plants or creepers absorb water through the water permeable holes, and do not require watering or sprinkler irrigation for maintenance.

4. The method for designing a unit-type anti-sliding retaining wall for a fill slope according to claim 1, characterized in that: The angle between the cone surface of the cone-shaped pull-out pier and the axis is 15°-30°.

Images