Counterfort retaining wall structure and construction method thereof

Abstract

The counterfort type retaining wall structure comprises a retaining wall, a receding platform and anchor cables, the retaining wall comprises an upper-layer retaining wall body and a lower-layer retaining wall body, the upper-layer retaining wall body is arranged on the upper portion of the rear portion of the lower-layer retaining wall body, and the receding platform is arranged between the upper-layer retaining wall body and the lower-layer retaining wall body; one end of each anchor cable is anchored on the lower-layer retaining wall, the other end of each anchor cable is fixed in a mountain behind the lower-layer retaining wall, supporting ribs are arranged on the rear sides of the upper-layer retaining wall and the lower-layer retaining wall, and graded broken stones are backfilled behind the upper-layer retaining wall and the lower-layer retaining wall. The invention further comprises a construction method of the counterfort type retaining wall structure, the upper-layer retaining wall and the lower-layer retaining wall are arranged in an up-down staggered mode, compared with a traditional gravity type retaining wall, the counterfort type retaining wall structure has the advantages that the soil pressure borne by the counterfort type retaining wall structure is greatly reduced, meanwhile, the concrete consumption of the upper-layer retaining wall and the lower-layer retaining wall is reduced, and the construction method belongs to the technical field of retaining walls.

Description

Technical Field

[0001] The present invention relates to the technical field of retaining walls, and particularly to a counterfort retaining wall structure and a construction method thereof. Background Art

[0002] In the field of geotechnical engineering, the high-fill slope retaining technology is widely used in road, bridge, mine and urban infrastructure construction. At present, traditional gravity retaining walls are still widely used in various retaining projects. This type of retaining wall mainly relies on its own weight to resist earth pressure, has a simple structure and convenient construction, and is suitable for engineering environments with good foundation bearing capacity.

[0003] However, in high-slope projects with relatively high fill heights, traditional gravity retaining walls have many technical bottlenecks. First of all, as the height of the wall increases, the earth pressure acting on the wall increases significantly, resulting in a substantial increase in the bending moment and shear force borne by the wall. To meet the requirements of structural stability, it is necessary to correspondingly increase the cross-sectional size and self-weight of the wall, thereby causing a sharp increase in material consumption, a rapid rise in project cost, and a significant decline in economy.

[0004] Secondly, since traditional gravity retaining walls rely on their own weight to maintain stability, their requirements for foundation bearing capacity also increase accordingly. Under soft or uneven foundation conditions, large-scale foundation treatment (such as reinforcement or pile foundation treatment) is often required, which not only increases the construction difficulty but also significantly increases the project cost.

[0005] In addition, once structural failures such as sliding and overturning occur in traditional gravity retaining walls, the repair is difficult, time-consuming and costly. According to statistics, if a high retaining wall over 15m experiences instability failure, the repair cost can reach 2-3 times that of a newly built structure, seriously restricting the feasibility of project later maintenance. Summary of the Invention

[0006] Aiming at the technical problems existing in the prior art, the object of the present invention is to provide a counterfort retaining wall structure and a construction method thereof, in which the upper retaining wall and the lower retaining wall are arranged in a vertically offset layout. Compared with traditional gravity retaining walls, the earth pressure borne by the counterfort retaining wall structure of the present invention is greatly reduced, and at the same time, the concrete consumption of the upper retaining wall and the lower retaining wall is also reduced.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A counterfort retaining wall structure includes a retaining wall, a setback platform and anchor cables. The retaining wall includes an upper retaining wall and a lower retaining wall, and the upper retaining wall is arranged at the upper rear part of the lower retaining wall. One end of the anchor cable is anchored on the lower retaining wall, and the other end of the anchor cable is fixed in the mountain body behind the lower retaining wall. Counterforts are arranged on the rear sides of both the upper retaining wall and the lower retaining wall. The spaces behind both the upper retaining wall and the lower retaining wall are backfilled with graded crushed stone. The setback platform is arranged between the upper retaining wall and the lower retaining wall.

[0009] As an optimization, both the upper retaining wall and the lower retaining wall include a retaining wall body and a bottom slab. The retaining wall body is arranged on the bottom slab. The bottom slab includes a heel and a toe, and the heel and the toe are integrally arranged. The heel is arranged behind the retaining wall body, and the toe is arranged in front of the retaining wall body.

[0010] As an optimization, multiple horizontal waist beams are arranged on the retaining wall body of the lower retaining wall, and the anchoring points of the anchor cables are arranged on the waist beams.

[0011] As an optimization, the retaining wall includes transverse steel bars and longitudinal steel bars. Multiple transverse steel bars and multiple longitudinal steel bars intersect vertically and horizontally to form a layer of steel mesh. Two layers of steel mesh are arranged on the front and rear sides inside the retaining wall body, two layers of steel mesh are arranged on the upper and lower sides inside the bottom slab, and two layers of steel mesh are arranged on both sides inside the counterfort. Multiple rib bars extending along the length direction of the outer side surface are arranged on the outer side surface of the counterfort. Multiple transverse beam bars and waist beam stirrups are arranged inside the waist beam. The waist beam stirrups are tied and fixed around the multiple transverse beam bars, and the multiple waist beam stirrups are arranged along the length direction of the transverse beam bars.

[0012] As an optimization, the retaining wall is equipped with a monitoring system. The monitoring system includes a laser generator, multiple optical fiber sensors, an optical signal conditioner and a computer terminal. The laser generator, the multiple optical fiber sensors, the optical signal conditioner and the computer terminal are electrically connected in sequence. The computer terminal is configured with finite element analysis software. The multiple optical fiber sensors are embedded in the retaining wall. In the retaining wall body, several optical fiber sensors are located inside the retaining wall body. A single optical fiber sensor extends along the length direction of the retaining wall body, and several optical fiber sensors are arranged along the height direction of the retaining wall body. There is an optical fiber sensor corresponding to each waist beam. In the bottom slab, several optical fiber sensors are arranged on the upper surface of the bottom slab. Several optical fiber sensors extend along the length direction of the bottom slab, and several optical fiber sensors are arranged along the width direction of the bottom slab. In the counterfort, an optical fiber sensor is arranged on the side surface of the counterfort facing the soil body.

[0013] As an optimization, the optical fiber sensor includes multiple optical fibers and multiple sensors. The optical fibers and the sensors are connected at intervals. The sensors are arranged on the transverse steel bars or rib bars through buckles. The sensors are connected to the buckles through bolts. The multiple buckles are respectively buckled on the transverse steel bars and the rib bars, and the multiple buckles are respectively welded to the transverse steel bars and the rib bars.

[0014] As an optimization, a layer of cohesive soil is laid on the setback platform.

[0015] As an optimization, a plurality of drain holes are provided on the retaining wall main body, and the drain holes communicate the front and rear of the retaining wall main body.

[0016] A construction method for a counterfort retaining wall structure, the construction steps are as follows: Step 1: Construct the lower retaining wall. First, level and compact the foundation, tie the steel bars at the corresponding lower retaining wall, install fiber optic sensors on the corresponding steel bars, and set the formwork of the lower retaining wall on the foundation; Step 2: Pour on the corresponding formwork to form the lower retaining wall, and then pre-embed the anchor cables after the lower retaining wall is completed; Step 3: When backfilling graded crushed stone behind the lower retaining wall, perform a compensation tension on the anchor cables every 3 m of backfill height until backfilled to the design elevation of the lower retaining wall; Step 4: Construct the upper retaining wall. Confirm the position of the upper retaining wall according to the length of the setback platform. First, level and compact the foundation of the upper retaining wall, tie the steel bars at the corresponding upper retaining wall, install fiber optic sensors on the corresponding steel bars, and set the formwork of the upper retaining wall on the foundation; Step 5: Pour on the corresponding formwork to form the upper retaining wall; Step 6: When backfilling graded crushed stone behind the upper retaining wall, perform a compensation tension on the anchor cables at the lower retaining wall every 3 m of backfill height until backfilled to the design elevation of the upper retaining wall, and lock the anchor cables after the tensioning is completed; Step 7: Lay a layer of cohesive soil on the setback platform.

[0017] As an optimization, in Steps 3 and 6, establish a three-dimensional model of the retaining wall in finite element analysis software. Before each backfill of graded crushed stone, obtain the initial strain value of the counterfort retaining wall structure through the fiber optic sensors. During the backfill process, collect the strain data through the fiber optic sensors to calculate the strain change amount, input the strain change amount into the finite element analysis software, and the finite element analysis software simulates the stress condition of the retaining wall, and perform the anchor cable tensioning correspondingly. After the tensioning, verify the strain value after the tensioning to ensure that the strain value after the tensioning is greater than or equal to 95% of the initial strain value.

[0018] The present invention has the following advantages:

[0019] (1) Through the cooperation of the upper retaining wall, the lower retaining wall and the anchor cables, there is a setback platform between the upper retaining wall and the lower retaining wall, and the upper retaining wall and the lower retaining wall form a stepped support for the high fill, which is beneficial to enhancing the stability of the mountain body / slope and reducing the occurrence of landslides.

[0020] (2) The upper retaining wall and the lower retaining wall are horizontally misaligned. Compared with the traditional single retaining wall structure, the earth pressure of the graded crushed stone backfill borne by the upper retaining wall or the lower retaining wall of the present invention is greatly reduced, and at the same time, the concrete consumption of the retaining wall is also reduced.

[0021] (3) The upper retaining wall and the lower retaining wall are both independent structural units. In case of slippage or deformation of some parts of the wall during use, only the independent structural unit needs to be repaired, reducing the repair cost.

[0022] (4) Multiple fiber optic sensors within the retaining wall form a sensing network, which can monitor stress and strain data in real time, detect the internal stress of the retaining wall, and transmit the stress and strain data to the monitoring system during the construction of the retaining wall to assist in the tensioning of the anchor cables, ensuring that the anchor cables can effectively assist the retaining wall in bearing the earth pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural diagram of the counterfort retaining wall structure of the present invention.

[0025] Figure 2 It is a schematic structural diagram of the lower retaining wall with the anchor cables and drainage holes removed according to the present invention.

[0026] Figure 3 For Figure 2 A schematic structural diagram from another angle.

[0027] Figure 4 It is a schematic structural diagram of the retaining wall body and the waist beam of the lower retaining wall.

[0028] Figure 5 It is a schematic structural diagram of the bottom plate.

[0029] Figure 6 It is a schematic structural diagram of the counterfort.

[0030] Figure 7 It is a schematic structural diagram of the steel bar configuration of the lower retaining wall.

[0031] Figure 8 For Figure 7 The sectional view of A-A of removing the waist beam.

[0032] Figure 9 It is a schematic structural diagram of the steel bar configuration of the concealed beam.

[0033] Figure 10 For Figure 9 The exploded view of the concealed beam stirrups.

[0034] Figure 11 It is a schematic structural diagram of the steel bar configuration of the waist beam.

[0035] Figure 12 It is a schematic structural diagram of an optical fiber sensor installed on a corresponding steel bar.

[0036] Among them, 1. Yielding platform; 2. Anchor cable; 3. Upper retaining wall; 4. Lower retaining wall; 5. Rib; 6. Anchor cap; 7. Mountain body; 8. Graded gravel; 9. Retaining wall main body; 10. Bottom slab; 11. Wall heel; 12. Wall toe; 13. Girder; 14. Transverse steel bar; 15. Longitudinal steel bar; 16. Rib steel bar; 17. Transverse beam steel bar; 18. Girder stirrup; 19. Hidden beam; 20. Hidden beam main steel bar; 21. First stirrup; 22. Second stirrup; 23. Third stirrup; 24. Optical fiber sensor; 25. Optical fiber; 26. Sensor; 27. Buckle; 28. Cohesive soil; 29. Drainage hole; 30. Ground; 31. Drainage ditch. Specific implementation mode

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the protection scope of the present invention.

[0038] As Figures 1 to 12 shown, a counterfort retaining wall structure includes a retaining wall, a yielding platform 1 and an anchor cable 2. The retaining wall includes an upper retaining wall 3 and a lower retaining wall 4. The upper retaining wall 3 is arranged at the upper rear part of the lower retaining wall 4. One end of the anchor cable 2 is anchored on the lower retaining wall 4, and an anchor cap 6 is arranged at the anchoring point of the anchor cable 2 on the lower retaining wall 4. The other end of the anchor cable 2 is fixed in the mountain body 7 behind the lower retaining wall 4, and the included angle between the anchor cable 2 and the horizontal plane is 30°. Ribs 5 are arranged on the rear sides of both the upper retaining wall 3 and the lower retaining wall 4. Graded gravel 8 is backfilled behind both the upper retaining wall 3 and the lower retaining wall 4, and the lower retaining wall 4 is located on the graded gravel 8. The yielding platform 1 is arranged between the upper retaining wall 3 and the lower retaining wall 4. The yielding platform 1 is the upper surface of the graded gravel 8 backfilled behind the lower retaining wall 4. The retaining wall bears the earth pressure of the mountain body 7 and the backfilled graded gravel 8 behind. The anchor cable is preferably a steel strand.

[0039] The present invention uses the synergistic effect of the upper retaining wall 3, the lower retaining wall 4 and the anchor cable 2, and there is a retreat platform 1 between the upper retaining wall 3 and the lower retaining wall 4. The upper retaining wall 3 and the lower retaining wall 4 form a step-like shape to support the high fill in a stepped manner, which is beneficial to enhance the stability of the mountain 7 or the slope and reduce the occurrence of landslides. Through experiments, the present invention can effectively deal with high fill projects with soft foundations with a height of more than 15 meters and a foundation bearing capacity of less than 120Kpa. The present invention can also be applied to mountain highway / railway subgrade fill projects, high and steep fill dams in water conservancy projects, and deep fill site slope support in urban construction, etc., which require breaking through the traditional retaining wall height limit.

[0040] In a traditional single retaining wall structure, as the wall increases, the load increases accordingly, and the bearing capacity of the foundation needs to be enhanced by expanding the foundation or performing ground treatment (such as pile foundation). The cost of ground treatment is high. However, in the present invention, the retaining wall is subjected to lower bending moment and better stability through the synergistic effect of the upper retaining wall 3, the lower retaining wall 4 and the anchor cable 2, and the cost is lower.

[0041] The lower retaining wall 4 and the upper retaining wall 3 are constructed one after the other. After the lower retaining wall 4 is completed, the upper retaining wall 3 is constructed using turnover materials such as formwork and scaffolding, which reduces the amount of turnover materials used compared to the traditional single retaining wall structure.

[0042] The upper retaining wall 3 and the lower retaining wall 4 are both independent structural units. If part of the wall slips or deforms during use, it is only necessary to repair the independent structural units, thereby reducing the repair cost.

[0043] In some embodiments, the upper retaining wall 3 and the lower retaining wall 4 both include a retaining wall body 9 and a bottom plate 10, and the retaining wall body 9 is arranged on the bottom plate 10; the bottom plate 10 includes a wall heel 11 and a wall toe 12, and the wall heel 11 and the wall toe 12 are arranged in an integrated manner, the wall heel 11 is arranged behind the retaining wall body 9, and the wall toe 12 is arranged in front of the retaining wall body 9. The width of the wall heel 11 is usually greater than the width of the wall toe 12. By designing the wall heel 11 and the wall toe 12 as an integrated structure and arranging them on the front and rear sides of the retaining wall body 9 respectively, the bottom plate 10 of the entire retaining wall forms a complete load-bearing and anti-slip system. This integrated design can effectively improve the overall anti-overturning and anti-slip capabilities of the retaining wall, thereby improving the stability of the retaining wall under soil pressure or other external forces. The wall heel 11 is located behind the retaining wall body 9, and can generate a greater anti-overturning moment when it is pushed by the mountain 7 behind it; while the wall toe 12 is located in front of the retaining wall body 9, which can effectively prevent the retaining wall from sliding forward and disperse the foundation stress. The synergistic effect of the two makes the retaining wall more evenly stressed under various loads, avoids local stress concentration, and improves the safety and durability of the structure.

[0044] In some embodiments, a plurality of horizontal waist beams 13 are provided on the retaining wall body 9 of the lower retaining wall 4. The anchoring points of the anchor cables 2 are arranged on the waist beams 13, and the anchor cap columns 6 are arranged on the waist beams 13. As a force transfer member between the anchor cables 2 and the retaining wall body 9, the waist beam 13 can more effectively transfer the tension of the anchor cables 2 to the retaining wall body 9, avoiding possible local damage or crack expansion when the anchor cables 2 are directly anchored to the retaining wall body 9. This structural form improves the bearing capacity and structural safety of the retaining wall under the action of large earth pressure or dynamic loads.

[0045] In some embodiments, preferably, the number of waist beams 13 is two, and the two waist beams 13 are arranged at intervals up and down. A plurality of anchor cables 2 arranged along the length direction of the waist beam 13 are provided on each waist beam 13. That is, there are two rows of anchor cables 2, upper and lower, in the present invention. The number of anchor cables 2 in each row is multiple, and the anchoring points of each row of anchor cables 2 on the waist beam 13 are arranged along the length direction of the waist beam 13. By providing two rows of anchor cables 2, upper and lower, in the lower retaining wall 4 of the present invention, the ability of the retaining wall body 9 to resist lateral pressure can be significantly improved, and the stability of the counterfort retaining wall structure under complex geological conditions can be enhanced.

[0046] In some embodiments, the upper retaining wall 3 can also be provided with waist beams 13 and anchor cables 2, and these variations are all within the protection scope of the present invention.

[0047] In some embodiments, preferably, the upper retaining wall 3, the lower retaining wall 4, and the ribs 5 are all made of C30 reinforced concrete structure. In the lower retaining wall 4, the total height is 10 meters, the width of the bottom slab 10 is 8 meters, the thickness of the retaining wall body 9 is 0.5 meters, a plurality of ribs 5 are arranged at intervals along the length of the lower retaining wall 4, the distance between two adjacent ribs 5 in the length direction of the lower retaining wall 4 is 4 meters, the thickness of the ribs 5 is 0.5 meters, the ribs 5 and the retaining wall body 9 are integrally cast, and the height of the ribs 5 is the same as the height of the lower retaining wall 4. In the upper retaining wall 3, the total height is 6 meters, the width of the bottom slab 10 is 8 meters, the thickness of the retaining wall body 9 is 0.5 meters, a plurality of ribs 5 are arranged at intervals along the length of the upper retaining wall 3, the distance between two adjacent ribs 5 in the length direction of the upper retaining wall 3 is 4 meters, the thickness of the ribs 5 is 0.5 meters, the ribs are integrally cast with the retaining wall body 9, and the height of the ribs 5 is the same as the height of the upper retaining wall 3. The width of the setback platform 1 is 6 meters. This is conducive to standardized construction and improves construction efficiency.

[0048] In some embodiments, the retaining wall includes transverse steel bars 14 and longitudinal steel bars 15. A plurality of transverse steel bars 14 and a plurality of longitudinal steel bars 15 intersect vertically and horizontally to form a layer of steel mesh. Two layers of steel mesh are arranged on the front and back sides inside the retaining wall body 9, two layers of steel mesh are arranged on the upper and lower sides inside the bottom slab 10, and two layers of steel mesh are arranged on both sides inside the ribs 5. As Figure 7 shown, the steel mesh of the ribs 5 is in Figure 7Only a partial view is shown herein and not all are drawn; multiple support bars (not shown in the figure) are respectively fixed between two layers of steel bar meshes inside the retaining wall main body 9, inside the bottom plate 10, and inside the rib 5, enhancing the overall stability and spatial positioning accuracy between the two layers of steel bar meshes. Multiple rib reinforcement bars 16 extending along the length direction of the outer side surface are arranged on the outer side surface of the rib 5. Specifically, the ends of the rib reinforcement bars 16 are bent into a hook shape and are tied to the two layers of steel bar meshes of the retaining wall main body 9; multiple transverse beam bars 17 and waist beam stirrups 18 are arranged inside the waist beam 13, and the waist beam stirrups 18 are tied and fixed around the multiple transverse beam bars 17, and the multiple waist beam stirrups 18 are arranged along the length direction of the transverse beam bars 17. Through reasonable steel bar arrangement, the stability, bearing capacity, construction accuracy, and seismic performance of the retaining wall structure are significantly improved, having good engineering application prospects and promotion value.

[0049] In some embodiments, two concealed beams 19 are arranged inside the bottom plate 10. The concealed beams 19 are made of the same material as the bottom plate 10 and extend along the length direction of the bottom plate 10. A concealed beam steel bar system is arranged inside the concealed beams 19. The concealed beam steel bar system includes multiple concealed beam main bars 20 and multiple concealed beam stirrups. The concealed beam main bars 20 extend along the length direction of the concealed beam 19, and the concealed beam main bars 20 are distributed on the inner side of the concealed beam 19 with a rectangular cross-section. The concealed beam stirrups are surrounded and tied around the multiple concealed beam main bars 20, and the multiple concealed beam stirrups are arranged along the length direction of the concealed beam main bars 20; the concealed beam stirrups include a first stirrup 21, a second stirrup 22, and a third stirrup 23. The first stirrup 21 surrounds and ties all the concealed beam main bars 20 that are fixed. The second stirrup 22 surrounds and ties the four concealed beam main bars 20 that are opposite to each other in the middle. The third stirrup 23 surrounds and ties the four concealed beam main bars 20 that are opposite to each other vertically. The first stirrup 21, the second stirrup 22, and the third stirrup 23 at the same position are overlapped and tied. The multiple first stirrups 21, second stirrups 22, and third stirrups 23 are all arranged along the length direction of the concealed beam main bars 20. The longitudinal steel bars 15 of the retaining wall extend into one of the concealed beam steel bar systems and are fixedly connected to the concealed beam steel bar system. Specifically, the lower ends of the longitudinal steel bars 15 are bent and tied to the concealed beam main bars 20, enhancing the rigidity and bearing capacity of the counterfort retaining wall structure.

[0050] The transverse steel bars 14, longitudinal steel bars 15, rib reinforcement bars 16, transverse beam bars 17, waist beam stirrups 18, concealed beam main bars 20, and concealed beam stirrups are collectively referred to as steel bars, and all the contact points of the steel bars are tied and fixed.

[0051] In some embodiments, a retaining wall configuration monitoring system is provided. The monitoring system includes a laser generator, multiple optical fiber sensors 24, an optical signal conditioner, and a computer terminal. The laser generator, the multiple optical fiber sensors 24, the optical signal conditioner, and the computer terminal are electrically connected in sequence. One end of each of the multiple optical fiber sensors 24 is electrically connected to the laser generator respectively, and the other end of each of the multiple optical fiber sensors 24 is connected to the optical signal regulator respectively. The computer terminal is configured with finite element analysis software. The multiple optical fiber sensors 24 are embedded in the retaining wall. The finite element analysis software can establish a three-dimensional model of the retaining wall and analyze the stress condition of the three-dimensional model of the retaining wall in real time. In the retaining wall main body 9, several optical fiber sensors 24 are located inside the retaining wall main body 9. Each single optical fiber sensor 24 extends along the length direction of the retaining wall main body 9, and several optical fiber sensors 24 are arranged along the height direction of the retaining wall main body 9. There is one optical fiber sensor 24 corresponding to each waist beam 13. In the bottom slab 10, several optical fiber sensors 24 are arranged on the upper surface of the bottom slab 10. Each of the several optical fiber sensors 24 extends along the length direction of the bottom slab 10, and several optical fiber sensors 24 are arranged along the width direction of the bottom slab 10. In the rib 5, one optical fiber sensor 24 is arranged on the side surface of the rib 5 facing the soil mass. The multiple optical fiber sensors 24 in the retaining wall form a sensing network, which can monitor the stress and strain data at the location where the optical fiber sensors 24 are located in real time, detect the internal stress change of the retaining wall, transmit the strain to the monitoring system when the graded broken stone 8 is backfilled in the retaining wall, and tension the anchor cable 2 through the data of the monitoring system to ensure that the anchor cable 2 can effectively assist the retaining wall to bear the soil pressure, reduce the soil pressure borne by the retaining wall to the target value, and improve the overall stability of the counterfort retaining wall structure. During use, when the optical fiber sensor 24 detects abnormal strain data, it can also give an early warning through the monitoring system, which is convenient for the staff to detect the counterfort retaining wall structure.

[0052] In some embodiments, the optical fiber sensor 24 includes multiple optical fibers 25 and multiple sensors 26. The optical fibers 25 are connected to the sensors 26 at intervals. The sensors 26 are arranged on the transverse steel bars 14 or the rib steel bars 16 through buckles 27. The sensors 26 are connected to the buckles 27 through bolts. One sensor 26 is arranged on two buckles 27. The two buckles 27 corresponding to one sensor 26 form a buckle combination. Multiple buckles 27 are respectively buckled on the transverse steel bars 14 and the rib steel bars 16, and multiple buckles 27 are respectively welded to the transverse steel bars 14 and the rib steel bars 16. The snap connection method enables the sensor 26 to be quickly positioned and fixed on the transverse steel bar 14 or the rib steel bar 16, improving the installation efficiency and construction convenience. The buckle 27 is fixed to the transverse steel bar 14 or the rib steel bar 16 by welding, ensuring that the sensor 26 is not easily displaced or detached during the construction of pouring concrete, thus ensuring the continuity and accuracy of the measurement data of the optical fiber sensor 24 and being beneficial to the long-term monitoring of the health status of the retaining wall.

[0053] In some embodiments, a layer of cohesive soil 28 is laid on the setback platform 1. The thickness of the cohesive soil 28 is 0.5 m. The cohesive soil 28 has a water-blocking effect to prevent rainwater from the upper part from infiltrating into the backfilled graded broken stone 8.

[0054] In some embodiments, a plurality of drain holes 29 are provided on the retaining wall main body 9. A drain pipe can be installed on the drain holes 29 to communicate the front and rear of the retaining wall main body 9. A drainage ditch 31 is provided above the toe 12 of the lower retaining wall 4, and a ground surface 30 is provided outside the toe 12. It can effectively discharge the accumulated moisture inside the retaining wall, reduce the pressure increase caused by moisture accumulation, thereby reducing the risk of the retaining wall being damaged due to excessive water pressure, and improving the overall safety and stability of the retaining wall.

[0055] In some embodiments, the present invention also protects a construction method of a counterfort retaining wall structure. The construction steps are as follows:

[0056] Step 1: Construct the lower retaining wall 4. First, level and compact the foundation, tie the steel bars at the corresponding position of the lower retaining wall 4, install the fiber optic sensor 24 on the corresponding steel bars, and set the formwork of the lower retaining wall 4 on the foundation.

[0057] Step 2: Pour concrete on the corresponding formwork to form the lower retaining wall 4. When pouring the concrete, monitor the survival rate of the fiber optic sensor 24 in real time. After the lower retaining wall 4 is completed, pre-embed the anchor cable 2.

[0058] Step 3: When backfilling the graded broken stone 8 behind the lower retaining wall 4, perform a compensation tensioning on the anchor cable 2 every 3 m of backfill height until the design elevation of the lower retaining wall 4 is reached. When tensioning the anchor cable 2, tension at the anchorage point of the anchor cable 2. Set a tensioner at the anchorage point of the anchor cable 2, and set a dynamometer on the tensioner. The dynamometer clamps one end of the anchor cable 2. When tensioning the anchor cable 2, measure the tension of the anchor cable 2 through the dynamometer.

[0059] Step 4: Construct the upper retaining wall 3. Confirm the position of the upper retaining wall 3 according to the length of the setback platform 1. First, level and compact the foundation of the upper retaining wall 3, tie the steel bars at the corresponding position of the upper retaining wall 3, install the fiber optic sensor 24 on the corresponding steel bars, and set the formwork of the upper retaining wall 3 on the foundation.

[0060] Step 5: Pour concrete on the corresponding formwork to form the upper retaining wall 3.

[0061] Step 6: When backfilling the graded broken stone 8 behind the upper retaining wall 3, perform a compensation tensioning on the anchor cable 2 at the lower retaining wall 4 every 3 m of backfill height until the design elevation of the upper retaining wall 3 is reached. After the tensioning of the anchor cable 2 is completed, lock it and cut off the exposed steel strands.

[0062] Step 7: Lay a layer of cohesive soil 28 on the setback platform 1.

[0063] In the above steps 3 and 6, a three-dimensional model of the retaining wall is established in the finite element analysis software. Before each backfilling of graded gravel 8, the initial strain value of the buttress retaining wall structure is obtained through the optical fiber sensor 24. During the backfilling process, strain data is collected by the optical fiber sensor 24 to calculate the strain change. The strain change after each stage of backfilling is input into the finite element analysis software through the controller. The finite element analysis software simulates the stress condition of the buttress retaining wall structure to obtain strain data output. The pre-tensioning force required for the anchor cable 2 to be tensioned is pre-tensioned accordingly. After the anchor cable 2 is tensioned, the strain value after tensioning is verified to ensure that the strain value of the buttress retaining wall structure after tensioning is greater than or equal to 95% of the initial strain value. By dynamically tensioning the anchor cable 2 through the cyclic process of "filling → tensioning → filling → tensioning", the strain of the retaining wall is accurately measured in cooperation with the optical fiber sensor 24 and fed back to the finite element analysis software, so that the tensioning force accuracy of the tensioning anchor cable 2 is improved, and the bearing capacity of the buttress retaining wall structure and the soil pressure balance of the high fill are accurately controlled, ensuring that the buttress retaining wall structure of the present invention effectively supports the high fill.

[0064] Traditional anchor cables are tensioned once after filling is completed, and the stress loss of traditional anchor cables is as high as 20%-30%, and the soil pressure change caused by backfilling cannot be compensated. The present invention adopts the "layered filling-dynamic tensioning" construction method, and implements compensation tensioning of anchor cable 2 every 3m of filling height, so that the effective prestress of anchor cable 2 is always maintained at more than 95% of the design value.

[0065] In the above step 4, when installing the optical fiber sensor 24, the surface of the transverse steel bars 14 and the rib steel bars 16 is polished with sandpaper to remove the oxide layer, and the optical fiber sensor 24 is arranged on the surface of the corresponding transverse steel bars 14 and the rib steel bars 16. A coupling agent is coated on the optical fiber 25 to enhance the adhesion with the transverse steel bars 14 and the rib steel bars 16. A plurality of clips 27 are respectively set on the transverse steel bars 14 or the rib steel bars 16, with a spacing of 30 cm between two adjacent clips. The sensor 26 is installed on the clip 27, and finally a 1 mm thick silicone protective layer is applied to the sensor 26.

[0066] The construction principle of the embedded anchor cable 2 in the above step 2: First, use a special drilling rig to drill holes in the mountain body 7 behind the lower retaining wall 4 at the other end of the anchor cable 2. The drilling is to provide a channel for the anchor cable 2 to enter the ground. After the drilling is completed, insert the prefabricated anchor cable 2 into the hole. The anchor cable 2 is usually made of high-strength steel strands, and special fittings such as pipes for grouting have been installed on the anchor cable 2. The next key step is to grout the hole: Generally, cement mortar is used, and the slurry is injected into the hole through the grouting pipe on the anchor cable 2 until the whole hole is filled. The purpose of doing this is to make the anchor cable 2 closely combine with the surrounding soil or rock, thereby increasing the friction and stability, and ensuring that the anchor cable 2 can effectively transfer the tensile force to the stable stratum. After the slurry reaches a certain strength, perform prestressed tension on one end of the anchor cable 2 at the retaining wall. After the tensioning is completed, anchor and lock the anchor cable 2 to maintain the applied tension.

[0067] The principle of the dynamic tension of the above anchor cable 2: By gradually tensioning the anchor cable 2 during the backfilling process, a dynamic balance is formed between the retaining force of the counterfort retaining wall structure and the gradually increasing earth pressure, thereby effectively controlling the lateral pressure received by the counterfort retaining wall structure, reducing the deformation of the main body 9 of the retaining wall, and improving the overall stability of the counterfort retaining wall structure. After each backfill of graded crushed stone 8 reaches a height of 3 meters, analyze the tensile force value required for the tension of the anchor cable 2 through finite element analysis software, and tension the anchor cable 2 according to the tensile force value. The anchor cable 2 generates a pre-tightening force, which is transmitted to the main body 9 of the retaining wall through components such as the waist beam 13 to assist the main body 9 of the retaining wall, and can reduce the earth pressure received by the main body 9 of the retaining wall, forming a combined stress system of the main body 9 of the retaining wall and the anchor cable 2, and reducing the foundation bearing capacity requirement of the counterfort retaining wall structure to 120 KPa.

[0068] The above further describes the present invention with reference to specific embodiments. However, it should be understood that the specific description here should not be construed as a limitation on the essence and scope of the present invention. Various modifications made by those of ordinary skill in the art to the above embodiments after reading this specification all fall within the scope protected by the present invention.

Claims

1. A counterfort retaining wall structure, characterized in that: It includes a retaining wall, a setback platform (1) and anchor cables (2). The retaining wall includes an upper retaining wall (3) and a lower retaining wall (4), and the upper retaining wall (3) is arranged at the upper rear of the lower retaining wall (4); one end of the anchor cable (2) is anchored on the lower retaining wall (4), and the other end of the anchor cable (2) is fixed in the mountain body (7) behind the lower retaining wall (4). Ribs (5) are arranged on the rear sides of both the upper retaining wall (3) and the lower retaining wall (4). Gradation gravel (8) is backfilled behind both the upper retaining wall (3) and the lower retaining wall (4). The setback platform (1) is arranged between the upper retaining wall (3) and the lower retaining wall (4).

2. The retaining wall structure according to claim 1, wherein: Both the upper retaining wall (3) and the lower retaining wall (4) include a retaining wall body (9) and a bottom slab (10), and the retaining wall body (9) is arranged on the bottom slab (10); the bottom slab (10) includes a heel (11) and a toe (12), the heel (11) and the toe (12) are integrally arranged, the heel (11) is arranged behind the retaining wall body (9), and the toe (12) is arranged in front of the retaining wall body (9).

3. The counterfort retaining wall structure according to claim 2, characterized in that: A plurality of transverse waist beams (13) are arranged on the retaining wall body (9) of the lower retaining wall (4), and the anchoring points of the anchor cables (2) are arranged on the waist beams (13).

4. A counterfort retaining wall structure according to claim 3, characterized in that: The retaining wall includes transverse steel bars (14) and longitudinal steel bars (15). A plurality of transverse steel bars (14) and a plurality of longitudinal steel bars (15) crisscross to form a layer of steel mesh. Two layers of steel mesh are arranged on the front and rear sides inside the retaining wall body (9), two layers of steel mesh are arranged on the upper and lower sides inside the bottom slab (10), and two layers of steel mesh are arranged on both sides inside the ribs (5); a plurality of rib steel bars (16) extending along the length direction of the outer side surface are arranged on the outer side surface of the ribs (5); a plurality of transverse beam bars (17) and waist beam stirrups (18) are arranged inside the waist beam (13), the waist beam stirrups (18) are tied and fixed on the periphery of the plurality of transverse beam bars (17), and a plurality of waist beam stirrups (18) are arranged along the length direction of the transverse beam bars (17).

5. A counterfort retaining wall structure according to claim 4, characterized in that: The retaining wall is equipped with a monitoring system. The monitoring system includes a laser generator, a plurality of optical fiber sensors (24), an optical signal conditioner and a computer terminal. The laser generator, the plurality of optical fiber sensors (24), the optical signal conditioner and the computer terminal are electrically connected in sequence, and the computer terminal is configured with finite element analysis software; the plurality of optical fiber sensors (24) are embedded in the retaining wall; in the retaining wall body (9), several optical fiber sensors (24) are located inside the retaining wall body (9), a single optical fiber sensor (24) extends along the length direction of the retaining wall body (9), several optical fiber sensors (24) are arranged along the height direction of the retaining wall body (9), and there is an optical fiber sensor (24) corresponding to each waist beam (13); in the bottom slab (10), several optical fiber sensors (24) are arranged on the upper surface of the bottom slab (10), several optical fiber sensors (24) extend along the length direction of the bottom slab (10), and several optical fiber sensors (24) are arranged along the width direction of the bottom slab (10); in the ribs (5), an optical fiber sensor (24) is arranged on the side surface of the ribs (5) facing the soil mass.

6. The counterfort retaining wall structure according to claim 5, wherein: The fiber optic sensor (24) includes a plurality of optical fibers (25) and a plurality of sensors (26). The optical fibers (25) are connected to the sensors (26) at intervals. The sensors (26) are arranged on the transverse steel bars (14) or the ribbed steel bars (16) through buckles (27). The sensors (26) are connected to the buckles (27) by bolts. A plurality of buckles (27) are respectively buckled on the transverse steel bars (14) and the ribbed steel bars (16), and a plurality of buckles (27) are respectively welded to the transverse steel bars (14) and the ribbed steel bars (16).

7. The counterfort retaining wall structure according to claim 1, characterized in that: Lay a layer of cohesive soil (28) on the retreat platform (1).

8. The retaining wall structure according to claim 2, characterized in that: A plurality of drain holes (29) are provided on the retaining wall main body (9), and the drain holes (29) communicate the front and the rear of the retaining wall main body (9).

9. The construction method of a counterfort retaining wall structure according to any one of claims 1 to 8, characterized in that: The construction steps are as follows: Step 1: Construct the lower retaining wall (4). First, level and compact the foundation, bind steel bars at the corresponding position of the lower retaining wall (4), install the fiber optic sensor (24) on the corresponding steel bars, and set the formwork of the lower retaining wall (4) on the foundation. Step 2: Pour concrete on the corresponding formwork to form the lower retaining wall (4). After the lower retaining wall (4) is completed, pre-embed the anchor cable (2). Step 3: When backfilling graded broken stone (8) behind the lower retaining wall (4), perform a compensation tension on the anchor cable (2) every time the backfill height reaches 3m until the backfill reaches the design elevation of the lower retaining wall (4). Step 4: Construct the upper retaining wall (3). Confirm the position of the upper retaining wall (3) according to the length of the retreat platform (1). First, level and compact the foundation of the upper retaining wall (3), bind steel bars at the corresponding position of the upper retaining wall (3), install the fiber optic sensor (24) on the corresponding steel bars, and set the formwork of the upper retaining wall (3) on the foundation. Step 5: Pour concrete on the corresponding formwork to form the upper retaining wall (3). Step 6: When backfilling graded broken stone (8) behind the upper retaining wall (3), perform a compensation tension on the anchor cable (2) at the lower retaining wall (4) every time the backfill height reaches 3m until the backfill reaches the design elevation of the upper retaining wall (3). After the tension of the anchor cable (2) is completed, lock it. Step 7: Lay a layer of cohesive soil (28) on the retreat platform (1).

10. The construction method of a counterfort retaining wall structure according to claim 9, characterized in that: In Step 3 and Step 6, establish a three-dimensional model of the retaining wall in the finite element analysis software. Before each backfilling of graded broken stone (8), obtain the initial strain value of the counterfort retaining wall structure through the fiber optic sensor (24). During the backfilling process, collect strain data through the fiber optic sensor (24) to calculate the strain change amount, input the strain change amount into the finite element analysis software, and the finite element analysis software simulates the stress condition of the retaining wall, and correspondingly performs the tension of the anchor cable (2). After the tension, verify the strain value after the tension to ensure that the strain value after the tension is greater than or equal to 95% of the initial strain value.

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