Design method of filling slope unit type anti-sliding retaining wall

Abstract

The invention relates to a method for designing a filling slope unit type anti-sliding retaining wall, which comprises the following steps of: dividing a slope into anti-sliding units by adopting a pulling-anchoring-separating-arranging composite structure, enabling a pull rod to penetrate through a filling area to oppositely pull a vertical retaining wall and a conical anti-pulling pier in undisturbed soil, and enabling the vertical retaining wall, the pull rod and a connecting beam to form a unit type closed structure for transmitting hoop force; and the cone uplift pier balances the gliding force of the inverted trapezoidal filling soil body, a drainage plate and a reinforced water-resisting layer are arranged below each pull rod downwards in the vertical direction, and the drainage plates are communicated to a drainage groove in the outer side of the retaining wall through a through-wall drainage pipe. The side slope retaining wall structure has the beneficial effects that the drainage plates and external drainage form a three-dimensional drainage system, and the problem that a conventional side slope retaining wall structure is only provided with drainage pipes on the surface and cannot achieve deep drainage of a filling area can be solved; the vertical retaining walls, the pull rods and the connecting beams form a unit type closed structure to transmit hoop force, the cone uplift piers balance gliding force of inverted trapezoidal filling unit soil bodies, and the anti-overturning capacity of a filling high slope and an anti-sliding wall can be improved.

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-sliding retaining wall. Background Art

[0002] The reasons for large-scale landslides on high fill slopes are, on the one hand, due to large-angle slope cutting and large-scale fill, the artificial slopes become steep or even upright, and the risk of slope foot instability is greatly increased. On the other hand, due to uneven settlement after large-scale fill foundation construction, cracks appear on the surface of the fill area. Heavy rains cause serious water accumulation and scouring on the surface, pouring the accumulated water into the cracks, washing away the sediment, forming gullies and gradually expanding. The infiltration increases the water pressure of the soil, reduces the shear strength of the soil, and causes large-scale landslides and collapses. In addition to the inducement of heavy rain disasters, the design pays attention to surface drainage, ignores the infiltration of accumulated water and the drainage of deep soil in the fill area, which is also the cause of landslide disasters.

[0003] Vertical retaining wall fill high slopes improve the utilization rate of construction sites more fully than slope-type high slopes. Common support methods include pile anchor support, gravity masonry retaining wall, large diameter anti-slide piles, buttress retaining wall, etc. Most drainage methods use slope surface drainage to remove slope surface water, and deep drainage is often ignored. Therefore, layered water isolation, deep drainage and reasonable anti-slide structure design are important considerations based on landslide principles and are important measures to reduce landslide risks, which deserve 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 landslide of fill slope, which is caused by the infiltration of surface water and groundwater, the silt is washed away and the shear strength of the fill foundation is reduced. A design method for a unit anti-sliding retaining wall for fill slope is provided, including adopting a pull-anchor-partition-row composite structure to form an anti-sliding system, using a pull rod to pull the upright retaining wall against the cone anti-pulling pier in the original soil, laying a layer of waterproof membrane + wire mesh + waterproof membrane sandwich structure reinforced waterproof layer under each pull rod in the vertical direction, and laying drainage boards on the reinforced waterproof layer at intervals. The drainage boards pass through the retaining wall and connect to 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. The problem that the conventional slope retaining wall structure only sets drainage pipes on the surface and cannot solve the deep drainage of the fill area can be solved, the anti-overturning ability of the high fill slope and the anti-sliding wall can be improved, the risk of shallow and deep landslides can be reduced, and the stability of the high slope in extreme rainstorm weather can be ensured.

[0005] The purpose of the present invention is achieved through the following technical solutions: A method for designing a unit-type anti-sliding retaining wall for a fill slope comprises the following steps: 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.

[0006] 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 position, 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.

[0007] S3. Backfill the 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 vibrate and compact it repeatedly. Then backfill and cast vertical retaining walls layer by layer. The height of the vertical retaining walls cast in sections is equal to the vertical spacing of the connecting beams.

[0008] 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 with anchor bars and tie rods. The length of the cone-shaped pull-out pier should meet the pull-out force requirements.

[0009] Furthermore, the length of the cone pull-out pier is determined by a pull-out test.

[0010] S5. When constructing the conical pull-out piers and connecting beams, the steel cage and supporting formwork of the vertical retaining wall are tied synchronously, and the support frame and through-wall drainage pipe of the wall drainage ditch are embedded in advance. A reinforced waterproof layer with a sandwich structure is laid on the earthwork at the elevation of the connecting beam.

[0011] 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, one end of the tie rod is anchored to the main reinforcement of the retaining wall of the vertical retaining wall, and the other end is connected to the anchor bar embedded in the conical pull-out pier and the connecting beam, and pour the vertical retaining wall concrete.

[0012] S7. Construct wall drainage grooves and planting grooves, and install the wall drainage grooves and planting grooves on the vertical retaining wall.

[0013] S8. Repeat steps S3-S7 until the earth is backfilled to the top of the slope, and the site concrete protective surface layer is poured or the highway roadbed is constructed.

[0014] 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.

[0015] Furthermore, when verifying the anti-sliding stability and safety of the unit anti-sliding retaining wall of the fill slope, 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 of 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 the fill and the original soil of the i-th fill unit, in kN; is the characteristic value of the pull-out force of a single cone 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.

[0016] Furthermore, the self-weight of the i-th fill unit is Calculate as follows: , where is the weight of the fill, in kN / m 3 .

[0017] 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: , where is the anti-sliding force of the interface between the fill and the original soil of the i-th fill unit, in kN / m 2 ; is the height of the i-th fill unit, in m; Furthermore, the total foundation reaction characteristic value of the i-th fill unit is Calculate as follows: , where is the characteristic value of the foundation reaction force per unit area of ​​the i-th fill unit, in kN / m 2 .

[0018] 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: , where The total horizontal anti-sliding force characteristic value per unit area provided by the reinforced waterproof layer and drainage board of the i-th fill unit, in kN / m 2 .

[0019] 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.

[0020] 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 fill unit, thereby maintaining the anti-sliding safety factor of the vertical retaining wall.

[0021] 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: .

[0022] Furthermore, a row of tie rods are laid at intervals on the drainage board and 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 and the tie rods are made of ribbed hot-rolled steel bars with a diameter of 25mm-40mm. The tie rods can be selected to be used alone or in pairs according to needs. The casing diameter is 50mm-100mm. The horizontal and vertical spacings 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.

[0023] Furthermore, the upright retaining wall, the tie rods and the connecting beams form a frame-type closed structure to transmit the clamping force to the fill, and the conical pull-out piers balance the downward force of the inverted trapezoidal fill.

[0024] Furthermore, the clamping force of the vertical retaining wall transmitted by the tie rods is arranged in units, and the downward sliding 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 anchor bars; the casing is not anchored to the vertical retaining wall and the connecting beam.

[0025] 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 the flowers, plants or vines absorb water through the water permeable holes and do not require watering or sprinkler irrigation for maintenance.

[0026] Furthermore, the reinforced waterproof layer includes a waterproof membrane and a steel wire mesh. The waterproof membrane is provided with two layers, and the steel wire mesh is sandwiched between the two layers of the 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.

[0027] Furthermore, the wire mesh plays a role of horizontal reinforcement for 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.

[0028] Furthermore, the drainage board consists of an upper permeable board, a lower board and a reinforced mesh board. The reinforced mesh board is arranged unidirectionally in a direction perpendicular to the vertical retaining wall. The mesh diameters of the upper permeable board and the reinforced mesh board are 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.

[0029] Furthermore, the angle between the cone surface of the cone-shaped anti-pull pier and the axis is 15°-30°.

[0030] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention sets multiple sandwich structure waterproof layers composed of waterproof membrane + wire mesh + waterproof membrane in the vertical high slope filling area, so that rainwater infiltrating into the ground from the surface 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 filling.

[0031] 2. The vertical high slope filling area of ​​the present invention is connected with the retaining wall and the cone anti-pulling pier through the tie rod. The vertical retaining wall, the tie rod and the connecting beam form a frame-type closed structure to transmit the hoop force to balance the downward force of the inverted trapezoidal filling soil. The tie rod sleeve is filled with asphalt to make the tie rod waterproof and rust-proof, and improve the durability of the tie rod. The sleeve is not subjected to force, so that the tension at both ends of the tie rod is equal, and the sleeve does not need to be made of high-strength material.

[0032] 3. The wall drainage trough and planting trough of the present invention are double-layer structures of cast-in-place concrete or steel plate welding. 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 moisture in the drainage trough, and no manual or sprinkler watering or maintenance is required.

[0033] 4. At the base of the vertical high slope fill area, block stone replacement filling layer is used 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.

[0034] 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

[0035] Figure 1 It is a first cross-sectional schematic diagram of the earth fill slope unit type anti-sliding retaining wall in the present invention; Figure 2 It is a second cross-sectional schematic diagram of the earth fill slope unit type anti-sliding retaining wall in the present invention; Figure 3 for Figure 1 A schematic diagram of the structure enlargement at point A; Figure 4 for Figure 1 A schematic diagram of the structure at B in FIG. Figure 5 for Figure 2 A schematic diagram of the structure at position C in FIG. Figure 6 for Figure 2 A schematic diagram of the structure at D in FIG. Figure 7 It is a schematic diagram of the cross-sectional structure of the pull rod in the present invention; Figure 8 It is a schematic diagram of the planar structure of the partition in the present invention; Fig. 9 It is a three-dimensional schematic diagram of the drainage board structure in the present invention; Fig.10 It is a schematic diagram of slope stability calculation and analysis in the present invention.

[0036] In the figure: 1. vertical retaining wall; 101. interface between fill and original soil; 102. wall drainage ditch; 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. dense nylon mesh; 602. earthwork; 603. through-wall drainage pipe; 604. upper permeable board; 605. lower board; 606. reinforced mesh board; 7. block stone replacement layer; 701. base drainage pipe; 8. planting trough; 801. planting soil; 802. flowers and plants; 803. partition; 804. permeable hole. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0038] A design method for a unit anti-sliding retaining wall for a fill slope adopts a tension-anchor-spacer-row composite anti-sliding structure to form an anti-sliding system. Specifically, a tension rod 3 is used to pull a vertical retaining wall 1 against a conical anti-pullout pier 2 in the original soil, and then a reinforced waterproof layer is laid at the elevation of each conical anti-pullout 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 grooves 102 on the vertical retaining wall 1. The drainage boards pass through the retaining wall to connect the wall drainage grooves 102. The wall drainage grooves and planting grooves 8 are double-layer structures. The middle partition 803 has water permeable holes 804, and the internal and external drainage structures form a three-dimensional drainage system.

[0039] The specific construction of the fill slope unit anti-slide retaining wall includes the following steps: S1, such as Fig.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.

[0040] 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 of the block stone replacement layer 7, and the base drainage pipe 701 is connected to the bottom drainage ditch 503.

[0041] 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, with the thickness of each layer not exceeding 500 mm, and is repeatedly vibrated and compacted using a rolling device, and 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.

[0042] S4, such as Figure 1 As shown, when the filling 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 cone pull-out pier 2 is pre-embedded with the cone pull-out pier main steel bar 203, the bottom of the cone pull-out pier 2 passes through the potential sliding surface and is embedded in the hard original soil or rock layer, and the angle between the cone surface of the cone pull-out pier 2 and the axis is 15°-30°. The head of the cone pull-out pier is connected to a whole by a connecting beam 201, and is welded to the tie rod 3 by an anchor bar 202, and the length of the cone pull-out pier should meet the pull-out force requirements.

[0043] Specifically, the length of the cone pull-out pier is determined through a pull-out test.

[0044] S5, such as Figure 1 , Figure 5 As shown, when constructing the conical pull-out pier and the connecting beam, the steel cage and the supporting formwork of the upright 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 advance, and a reinforced waterproof layer with a sandwich structure is laid on the earth at the elevation of the connecting beam 201.

[0045] S6, such as Figure 1 , Figure 3-Figure 5 As shown, 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 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, and the other end is welded to the anchor bar 202 embedded in the cone pull-out pier 2 and the connecting beam 201, and the concrete of the vertical retaining wall 1 is poured. The casing 301 is not anchored to the vertical retaining wall 1 and the connecting beam 201.

[0046] 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).

[0047] S8, such as Figure 1 As shown, steps S3-S7 are repeated until the earthwork is backfilled to the top of the slope, and the site concrete protective surface layer is poured or the highway roadbed is constructed.

[0048] S9, such as Figure 1 , Figure 2 , Figure 6As shown, an intercepting ditch 501 is arranged on the inner side of the top surface of the high slope of the vertical retaining wall, and a top drainage ditch 502 is arranged 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.

[0049] The present invention provides a design method for a unit anti-sliding retaining wall for a fill slope. According to the instability mechanism of the fill slope landslide, which is caused by the infiltration of surface water and groundwater, the silt is washed away and the shear strength of the fill foundation is reduced. A pull-anchor-spacer-row composite structure is used to form an anti-sliding system. A pull rod 3 is arranged between the vertical retaining wall 1 and the cone pull-out pier 2 to transmit the vertical retaining wall clamp force. The cone pull-out pier 2 balances the downward force of the inverted trapezoidal fill soil body and protects the fill soil from being washed away by rainwater. Multiple reinforced waterproof layers composed of waterproof coiled material 4+wire mesh 401+waterproof coiled material 4 are arranged in the vertical high slope fill area to isolate the accumulated water infiltrated from the surface underground in layers, and drained away by drainage boards, so as to keep the shear strength of the soil body from being reduced. The bottom partition of the planting trough 8 has a water-permeable hole so that the roots of flowers, plants or creepers in the planting trough pass through the water-permeable hole to absorb the water in the drainage trough, and no manual or sprinkler irrigation and watering maintenance is required. 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.

[0050] 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.

[0051] like Figure 1 , Figure 4 As shown, after each layer of earthwork is backfilled, it is repeatedly vibrated and compacted by rolling equipment, and the backfill thickness of each layer of earthwork does not exceed 500mm; the length of the cone pull-out pier 2 is determined by the pull-out test, so that the cone pull-out pier 2 meets the pull-out resistance requirements. The frame-type closed structure composed of the vertical retaining wall 1, the tie rod 3, and the connecting beam 201 transmits the hoop force to the backfill, thereby locking the downward trend of the inverted trapezoidal backfill soil.

[0052] 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, and the diameter of the sleeve 301 is 50mm-100mm. 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.

[0053] In this embodiment, the horizontal spacing between the tie rods 3 and the horizontal spacing between the cone-shaped anti-pull piers 2 are both 2m-4m, and the vertical spacing between the tie rods 3 and the vertical spacing between the cone-shaped anti-pull piers 2 are both 3m-5m.

[0054] like Figure 6 , Figure 8 As shown, the wall drainage groove 102 and the planting groove 8 are a double-layer structure made of cast-in-place concrete or steel plate welding. The planting groove 8 is located above the wall drainage groove 102. A partition 803 is provided at the bottom of the planting groove 8. A water-permeable hole 804 is provided on the partition 803. In addition, a water retaining plate not less than 10 mm high is provided at the water outlet of the wall drainage groove 102 to maintain 10 mm high water accumulation in the wall drainage groove 102. The partition 803 is rectangular and laid along the planting groove 8. The wall drainage groove 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 groove 8. The roots of the flowers and plants or creepers pass through the water-permeable holes 804 to absorb the moisture in the wall drainage groove 102, and do not need watering or sprinkler irrigation maintenance.

[0055] like Figure 5 As shown, the reinforced waterproof layer includes a waterproof coiled material 4 and a steel mesh 401. When laying the reinforced waterproof layer, first lay a layer of waterproof coiled material 4, then lay a layer of steel mesh 401, and finally cover a layer of waterproof coiled material 4, and then sandwich the steel mesh 401 between the two layers of waterproof coiled material 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 play a horizontal reinforcement role on the fill layer, and improve the tensile strength and shear strength of the soil. Through the setting of the reinforced waterproof layer, the rainwater that infiltrates from the surface to the ground can be isolated in layers and drained away by the drainage board 6, 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.

[0056] like Fig. 9 As shown, the drainage board 6 is composed of an upper permeable board 604, a lower board 605 and a stiffened mesh board 606. The stiffened mesh board 606 is arranged unidirectionally in a direction perpendicular to the vertical retaining wall 1. The mesh diameters of the upper permeable board 604 and the stiffened mesh board 606 are 2mm-3mm, and the mesh spacing is 10mm-20mm. The top and side surfaces of the drainage board 6 are wrapped with 1-2 layers of dense nylon mesh 601 to filter sediment. The drainage board is placed directly on the reinforced waterproof layer, maintaining a drainage slope of not less than 0.3%. One end of the drainage board 6 is inserted into the original soil combined slope, and the other end is connected to the through-wall drainage pipe 603.

[0057] like Fig.10 As shown, the present invention adopts the anti-sliding safety factor of the layered unit of the fill area and the safety factor of the layered unit foundation bearing capacity to verify the anti-sliding stability and safety of the unit anti-sliding retaining wall of the fill slope. 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: Verify the anti-sliding stability of the fill layer unit. Fig.10 As shown in the figure, the height and unit width of the fill soil 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 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 the fill and the original soil of the i-th fill unit, in kN; is the characteristic value of the pull-out force of a single cone 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 fill and original soil.

[0058] Specifically, the self-weight of the i-th fill unit is Calculate as follows: , where is the weight of the fill, in kN / m 3 .

[0059] 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: , where is the anti-sliding force of the interface between the fill and the original soil of the i-th fill unit, in kN / m 2 ; is the height of the i-th fill unit, in meters.

[0060] Specifically, the total foundation reaction characteristic value of the i-th fill unit is Calculate as follows: , where is the characteristic value of the foundation reaction force per unit area of ​​the i-th fill unit, in kN / m 2 .

[0061] Specifically, 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: , where The total horizontal anti-sliding force characteristic value per unit area provided by the reinforced waterproof layer and drainage board of the i-th fill unit, in kN / m 2 .

[0062] Specifically, 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.

[0063] 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 fill unit, thereby maintaining the anti-sliding safety factor of the vertical retaining wall.

[0064] Verify the safety of the fill layer unit. Fig.10 As shown in the figure, 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: .

[0065] Although 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 the embodiments without departing from the principles and spirit of the invention, and the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for designing a unit-type anti-sliding retaining wall for a fill slope, characterized in that: The following steps are involved: S1. Determine the structural parameters of the vertical retaining wall (1) and the fill slope design parameters, and verify that the anti-sliding stability and safety of the fill slope unit anti-sliding retaining wall meet the design requirements; S2, excavating the vegetation layer and root soil at the interface (101) between the fill and the original soil, 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 retaining wall construction position, burying a bottom drainage pipe (701) at the bottom surface of the block stone replacement layer (7), and connecting the bottom drainage pipe (701) to the bottom drainage ditch (503); S3, backfilling soil (602) in layers from the block stone replacement layer (7) in the backfill area upwards, 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 a vertical retaining wall (1) layer by layer upwards, with the height of the vertical retaining wall (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-shaped anti-pullout pier (2), the cone-shaped anti-pullout pier (2) is constructed on the original soil slope. The bottom of the cone-shaped anti-pullout pier (2) passes through the potential sliding surface and is embedded in the hard original soil or rock layer. The head of the cone-shaped anti-pullout pier (2) is connected to form a whole with a connecting beam (201) and is welded to the tension rod (3) through anchor bars (202). The length of the cone-shaped anti-pullout pier (2) should meet the pullout force requirements. The length of the cone-shaped anti-pullout pier (2) is determined by a pullout test. S5. When constructing the cone-shaped anti-pulling pier and the connecting beam, the steel cage and the supporting formwork of the vertical retaining wall (1) are simultaneously tied, and the support frame and the through-wall drainage pipe (603) of the wall drainage trough (102) are pre-embedded in the steel cage of the vertical retaining wall (1), and a reinforced waterproof layer with a sandwich structure is laid on the earthwork at the elevation of the connecting beam (201); S6. A drainage board (6) wrapped with 1-2 layers of dense nylon mesh (601) is laid above the reinforced waterproof layer, and a tie rod (3) is embedded above the drainage board (6). 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-shaped anti-tension pier (2) and the connecting beam (201), and the vertical retaining wall (1) is poured with concrete; 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, repeating steps S3-S7 until the earthwork 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 method for designing a unit-type anti-sliding retaining wall for fill slope according to claim 1, characterized in that: When checking the anti-sliding stability and safety of the unit anti-sliding retaining wall of the fill slope, the specific calculation 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, and use the formula Calculate the anti-sliding stability of the i-th layer of 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 waterproof layer 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 the fill and the original soil of the i-th fill unit, in kN; is the characteristic value of the pull-out force of a single cone 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 fill and original soil; Self-weight of the i-th fill unit By formula Calculate, where is the weight of the fill, in kN / m 3 ; The total anti-sliding force characteristic value of the interface between fill and original soil of the i-th fill unit By formula Calculate, where is the anti-sliding force of the interface between the fill and the original soil of the i-th fill unit, in kN / m 2 ; is the height of the i-th fill unit, in m; Eigenvalue of total foundation reaction force for the i-th fill unit By formula Calculate, 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 ; The total horizontal anti-sliding force characteristic value provided by the reinforced waterproof layer and drainage board of the i-th fill unit By formula Calculate, where The total horizontal anti-sliding force characteristic value per unit area provided by the reinforced waterproof layer and drainage board of the i-th fill unit, in kN / m 2 ; Characteristic value of the pull-out force of a single cone-shaped pull-out pier in the i-th layer of fill unit Determined by pull-out test; 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 fill unit, so as to maintain the anti-sliding safety factor of the vertical retaining wall. Safety factor of foundation bearing capacity of the i-th fill unit By formula calculate, .

3. The method for designing a unit-type anti-sliding retaining wall for fill slope according to claim 1, characterized in that: A row of tie rods (3) are laid on the drainage board (6) at intervals. The tie rods (3) are inserted into the casing (301). The tie rods (3) are subjected to stress, while the casing (301) is not subjected to stress. The casing (301) is filled with asphalt (302). The tie rods (3) are made of ribbed hot-rolled steel bars with a diameter of 25 mm-40 mm. The tie rods (3) are selected to be used in single or double pieces according to needs. The diameter of the casing (301) is 50 mm-100 mm. The horizontal spacing of the tie rods (3) and the vertical spacing of the tie rods (3) are consistent with those of the cone pull-out pier (2). The horizontal spacing of the tie rods (3) is 2 m-4 m, and the vertical spacing of the tie rods (3) is 3 m-5 m. The casing (301) is filled with asphalt (302) to prevent the tie rods (3) from rusting.

4. The method for designing a unit-type anti-sliding retaining wall for fill slope according to claim 1, characterized in that: The upright retaining wall (1), the tie rod (3) and the connecting beam (201) form a frame-type closed structure to transmit the clamping force to the fill soil, and the conical anti-pullout pier (2) balances the downward force of the inverted trapezoidal fill soil body.

5. The method for designing a unit-type anti-sliding retaining wall for fill slope according to claim 1, characterized in that: The vertical retaining wall clamp force transmitted by the pull rod (3) is arranged in units, and the downward force of the inverted trapezoidal fill soil is balanced by the conical pull-out pier (2). One end of the pull rod (3) is bent and anchored in the vertical retaining wall (1), and the other end is welded to the conical pull-out pier through the anchor bar (202), while the sleeve (301) is not anchored to the vertical retaining wall (1) and the connecting beam (201).

6. The method for designing a unit-type anti-sliding retaining wall for fill slope according to claim 1, characterized in that: The wall drainage trough (102) and the planting trough (8) are integrally formed into 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). A water retaining plate having a height of not less than 10 mm is provided at the water outlet of the wall drainage trough (102) 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 is 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 need watering or sprinkler irrigation for maintenance.

7. The method for designing a unit-type anti-sliding retaining wall for fill slope according to claim 1, characterized in that: The reinforced waterproof layer comprises a waterproof coiled material (4) and a steel wire mesh (401). The waterproof coiled material (4) is provided with two layers. The steel wire mesh (401) is sandwiched between the two layers of the waterproof coiled material (4). The reinforced waterproof layer is provided with a drainage slope of not less than 0.3% from the inside to the outside, so as to prevent the water accumulated in the upper layer of fill from penetrating into the lower layer.

8. The method for designing a unit-type anti-sliding retaining wall for fill slope according to claim 7, characterized in that: The steel wire mesh (401) 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 steel wire mesh (401) is 1 mm to 3 mm, and the mesh spacing of the steel wire mesh (401) is 50 mm to 100 mm.

9. The method for designing a unit-type anti-sliding retaining wall for fill slope according to claim 1, characterized in that: The drainage board (6) is composed of an upper permeable board (604), a lower board (605) and a reinforced mesh board (606). The reinforced mesh board (606) is arranged in one direction perpendicular to the vertical retaining wall (1). The mesh diameters of the upper permeable board (604) and the reinforced mesh board (606) are 2 mm to 3 mm, and the mesh spacing is 10 mm to 20 mm. The top and side surfaces of the drainage board (6) are wrapped with 1 to 2 layers of dense nylon mesh (601) to filter sediment. The drainage board is directly placed on the reinforced waterproof layer to maintain 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 (603).

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

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