Reinforced shore-based mooring assembly for inland river immersed tube tunnel and method of construction thereof

Abstract

The present application relates to the technical field of immersed tunnel construction, and particularly relates to a reinforced shore-based mooring assembly for an inland river immersed tunnel and a construction method thereof; the shore-based mooring assembly comprises a reinforced foundation block, an enlarged foundation and a mooring piece; the reinforced foundation block penetrates a silt layer and is partially embedded in a sandy layer; the reinforced foundation block has a foundation pit with an opening facing upwards; the enlarged foundation is poured into the foundation pit and forms an integral structure with the reinforced foundation block; the lower end of the mooring piece is embedded in the enlarged foundation, and the upper end vertically extends out of the enlarged foundation and is used for connecting a mooring column on the immersed tunnel through a steel wire rope; the enlarged foundation is arranged on the reinforced foundation block to prevent uneven settlement of the enlarged foundation caused by river water erosion and soaking; after the reinforced foundation block penetrates the silt layer, the reinforced foundation block is embedded in the sandy layer to avoid slippage or overturning of the mooring piece caused by huge tension during the process of immersed tunnel reeling; the reinforced foundation block has small disturbance in high-pressure jet grouting pile reinforcement construction, does not need large pile driving equipment and is suitable for narrow inland river shore construction.

Description

Technical Field

[0001] This invention relates to the field of immersed tunnel construction technology, and in particular to a reinforced shore-based mooring assembly for inland river immersed tunnels and its construction method. Background Technology

[0002] In the construction of immersed tunnels in inland rivers, the tunnel segments are typically transported and installed using a winch-movement method. The displacement of the immersed tunnel is achieved by the coordinated operation of the shore-based mooring components, which involve the raising and lowering of the wire ropes. The shore-based mooring components mainly consist of winches and guide bollards. After the immersed tunnel segments are prefabricated in the dry dock, they are floated, leak-tested, and the dock gate is removed. Then, the winch wire rope is passed through the guide bollards and connected to the mooring bollards of the immersed tunnel segments.

[0003] To ensure smooth rope delivery and unloading from the winch, the wire rope's exit direction should be as perpendicular as possible to the drum axis. Therefore, guide posts must be installed on land near the winch. The wire rope passes around the guide posts, which can change the direction of the wire rope entering and exiting the winch. In addition, due to the limitations of the winch's location or the need for cable repositioning, additional guide posts may be required on land.

[0004] During the winding and installation of the immersed tunnel, the tension of the wire rope is required to ensure the stability of the tunnel. The tension of the wire rope is determined by the tightness of the wire rope. If the guide post or winch foundation on which a wire rope is located slips or overturns, it will cause the tunnel to lose its attitude and lead to serious safety accidents such as collisions or installation failures.

[0005] The foundations for the winches and guide bollards in inland river immersed tunnel projects are usually located on the riverbank. Inland rivers are affected by flood season and storm surge, resulting in large water level fluctuations. The banks are composed of alluvial soft silty soil layers. The foundations for the winches and guide bollards are usually steel pipe pile foundations. However, steel pipe piles are expensive, and the shallow water at the riverbank makes it impossible for pile driving boats to operate. Furthermore, mechanical equipment such as crawler cranes causes significant damage to the riverside roads, making construction difficult.

[0006] Therefore, a low-cost and easy-to-construct reinforced shore-based mooring assembly for inland river immersed tunnels and its construction method are proposed to improve the anti-slip and anti-overturning capabilities of the shore-based mooring assembly foundation. Summary of the Invention

[0007] To address the shortcomings of the existing technology, this invention provides a reinforced shore-based mooring component and its construction method that can ensure the foundation of the shore-based mooring component does not slip or overturn in inland river immersed tunnels.

[0008] On one hand, this application provides a reinforced shore-based mooring assembly for inland river immersed tunnels, disposed on a soft foundation, the soft foundation comprising a surface silt layer and a sandy layer below the silt layer, the shore-based mooring assembly comprising: A reinforced foundation block penetrates the silt layer, and the lower part of the reinforced foundation block is embedded in the sandy layer. The reinforced foundation block has an opening facing upwards in the foundation pit. An enlarged foundation is poured into the foundation pit to form an integral structure with the reinforced foundation block, and the upper part of the enlarged foundation protrudes from the upper surface of the reinforced foundation block; at least three sets of steel mesh are provided inside the enlarged foundation, and each set of steel mesh is arranged parallel to each other and spaced apart in the vertical direction within the enlarged foundation to improve the bearing capacity of the enlarged foundation; A mooring component, which is installed on the enlarged foundation and extends vertically from the enlarged foundation at its upper end, is used to connect with a mooring bollard on the immersed tube via a steel wire rope. The mooring component is a winch or a guide bollard.

[0009] In some embodiments of this application, a gravel layer and / or a concrete cushion layer are provided between the bottom surface of the enlarged foundation and the foundation pit. The gravel layer and the concrete cushion layer are used to increase the friction between the enlarged foundation and the reinforced foundation block, thereby further improving the anti-slip capability of the enlarged foundation.

[0010] In some embodiments of this application, the height of the enlarged foundation is 1.5-2.0m and the depth of the pit is 1m, which improves the anti-slip and anti-overturning capabilities of the enlarged foundation.

[0011] In some embodiments of this application, when the mooring element is a guide post, its lower end is pre-embedded in the enlarged foundation, and its upper end extends vertically out of the enlarged foundation. The portion of the guide post extending out of the enlarged foundation is used for wire rope winding.

[0012] In some embodiments of this application, when the mooring element is a winch, the winch is fixed to the enlarged foundation by embedded parts.

[0013] On the other hand, this application also provides a construction method for the above-mentioned reinforced shore mooring assembly, including the following steps: Preparation: Measure and mark out the construction location of the mooring components; Construction of reinforced foundation blocks: The foundation at the construction site is reinforced using the high-pressure jet grouting method, and the resulting high-pressure jet grouting piles serve as reinforced foundation blocks; Excavation of the foundation pit: When the strength of the high-pressure jet grouting pile reaches more than 70% of the design value, the reinforced foundation block is excavated to form the foundation pit; Pouring the spread foundation: Lay steel mesh at the construction location of the spread foundation and pour concrete to form the spread foundation; Install the mooring components: Install the mooring components on the enlarged foundation.

[0014] In some embodiments of this application, in the construction steps of the reinforced foundation block, the high-pressure jet grouting pile method adopts the double-pipe method, the water-cement ratio of the grout is 1.0, the grouting pressure is greater than 20MPa, the flow rate is greater than 30L / min, the drilling speed is 1m / min, and the lifting speed is 0.1-0.2m / min.

[0015] In some embodiments of this application, when the mooring element is a guide bollard, in the step of pouring the enlarged foundation, after the steel mesh is laid, the lower structure of the guide bollard is fixed to the steel mesh, and then concrete is poured to form the enlarged foundation, and the guide bollard installation is completed; the guide bollard can be used when the strength of the enlarged foundation reaches the design strength.

[0016] In some embodiments of this application, when the mooring component is a winch, in the step of pouring the enlarged foundation, after the steel mesh is laid, the embedded parts are installed, and then concrete is poured to form the enlarged foundation; the winch is fixed to the embedded parts to realize the installation of the winch.

[0017] In some embodiments of this application, after the foundation pit is excavated, a 0.3m thick layer of crushed stone is first laid on the bottom surface of the foundation pit, and then a 0.1m thick layer of concrete is poured as a concrete cushion layer to improve the anti-slip and anti-overturning capacity of the spread foundation.

[0018] In some embodiments of this application, before pouring the enlarged foundation, it is necessary to erect a template on the upper surface of the reinforced foundation block above the foundation pit in order to pour the enlarged foundation that protrudes from the upper surface of the reinforced foundation block.

[0019] Based on the above technical solution, the reinforced shore mooring component of the present invention is applicable to the situation where the foundation of the guide cable post or winch of the mooring component is located on the soft foundation of the riverbank during the inland river immersed tube relocation process. The enlarged foundation is set on the reinforced foundation block, which can prevent the uneven settlement of the enlarged foundation caused by the scouring and soaking of river water. Compared with the enlarged foundation being directly poured on the soft soil foundation, the setting of the reinforced foundation block greatly improves the overturning resistance of the mooring component. The reinforced foundation block penetrates the silt layer, and some of the reinforced foundation blocks are embedded in the underlying sandy layer. The reinforced foundation block prevents the guide cable column or winch from bearing huge tension during the sinking pipe movement process, thus preventing the foundation from slipping or overturning. The reinforced foundation block of the present invention is formed by high-pressure jet grouting piles to reinforce the soft soil foundation. Compared with steel pipe piles, high-pressure jet grouting piles cause less disturbance during construction, do not require large pile driving equipment, and the jet grouting equipment is small in size, mobile and flexible, and suitable for construction on narrow inland riverbanks. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram showing the positional relationship between the mooring element (a guide bollard) and the immersed tube and winch in an embodiment of the present invention. Figure 2 This is a schematic diagram of the reinforced shore-based mooring assembly structure when the mooring component is a winch in an embodiment of the present invention; Figure 3 This is a schematic diagram showing the distribution of the reinforcing mesh in the foundation pit at position J7 in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the distribution of high-pressure jet grouting piles in the reinforced foundation block according to an embodiment of the present invention; Figure 5 This is a schematic diagram showing the distribution of the winch and cable guide post in Embodiment 1 of the present invention; Figure 6 This is a schematic diagram showing the location distribution of the winch embedded parts at position J7 in Embodiment 1 of the present invention; Figure 7 This is a top view of the anchor plate and anchor bar at position J7 in Embodiment 1 of the present invention; Figure 8 This is a left view of the anchor plate and anchor bar at position J7 in Embodiment 1 of the present invention; Figure 9 This is a schematic diagram showing the distribution of the reinforcing mesh in the foundation pit at position D16 in Embodiment 1 of the present invention; Figure 10 This is a schematic diagram showing the position of the cable guide post at location D16 in the steel mesh in Embodiment 1 of the present invention.

[0021] In the diagram, 10 is the reinforced foundation block; 11 is the high-pressure jet grouting pile; and 12 is the foundation pit. 20. Enlarged foundation; 21. Steel mesh; 30. Cable guide post; 40. Winch; 41. Anchor plate; 42. Anchor bar; 50. Wire rope; 60. Submerged tube; 61. Mooring bollard. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] An illustrative embodiment of the present invention provides a reinforced shore-based mooring assembly for an inland river immersed tunnel, which is disposed on a soft foundation. The soft foundation includes a surface silt layer and a sandy layer below the silt layer. The shore-based mooring assembly includes a reinforced foundation block 10 formed by reinforcing the soft foundation, an enlarged foundation 20 disposed within the reinforced foundation block 10, and mooring components fixed to the enlarged foundation 20.

[0026] Specifically, such as Figure 1 As shown, the reinforced foundation block 10 penetrates the silt layer from top to bottom. The lower part of the reinforced foundation block 10 is embedded in the sandy layer below. The upper part of the reinforced foundation block 10 has an opening-facing pit 12. The enlarged foundation 20 is poured into the pit 12 and forms an integral structure with the reinforced foundation block 10. The upper part of the enlarged foundation 20 protrudes from the upper surface of the reinforced foundation block 10. The lower end of the mooring piece is embedded in the enlarged foundation 20, and the upper end of the mooring piece extends vertically out of the enlarged foundation 20. The mooring piece is used to connect with the mooring post 61 on the immersed tube 60 through a wire rope 50. The mooring piece described in this application is a guide post 30 or a winch 40.

[0027] In some embodiments, when the mooring element is a guide post 30, such as Figure 1 As shown, the lower part of the guide post 30 is located inside the enlarged base 20, and the upper part of the guide post 30 extends out of the enlarged base 20. The guide post 30 is used for winding the wire rope 50 and restricting the direction of the wire rope entering and exiting the winch 40, so that the direction of the wire rope 50 is perpendicular to the drum.

[0028] In some embodiments, when the mooring element is a winch 40, such as Figure 2As shown, the winch 40 is fixed to the enlarged foundation 20 by embedded parts. The embedded parts are generally anchor plates 41 and anchor bars 42. The embedded parts transfer the load of the winch to the enlarged foundation 20, which increases the load-bearing area, provides anti-overturning weight, and distributes the load.

[0029] In some embodiments, the height of the enlarged foundation 20 is 1.5-2.0m, and the depth of the pit 12 is 1m, that is, the burial depth of the enlarged foundation 20 in the pit 12 is 1m, which improves the anti-slip and anti-overturning capabilities of the enlarged foundation 20.

[0030] In some embodiments, a gravel layer and a concrete cushion layer are sequentially provided between the bottom surface of the enlarged foundation 20 and the foundation pit 12 from bottom to top, in order to increase the friction between the enlarged foundation 20 and the reinforced foundation block 10, and further improve the anti-slip capability of the enlarged foundation 20.

[0031] In some embodiments, such as Figure 3 As shown, the enlarged foundation 20 has at least three sets of steel mesh 21 inside, with each set of steel mesh 21 arranged parallel to each other and spaced apart in the vertical direction to improve the bearing capacity of the enlarged foundation 20.

[0032] On the other hand, this application also provides a construction method for the above-mentioned reinforced shore mooring components, including the following steps: Preparation: Measure and mark out the construction location of the reinforced foundation block 10; Construction of reinforced foundation blocks: The foundation at the construction site is reinforced by high-pressure jet grouting, and the resulting high-pressure jet grouting piles 11 serve as reinforced foundation blocks 10; Excavation of the foundation pit: When the pile strength of the high-pressure jet grouting pile 11 reaches more than 70% of the design value, the reinforced foundation block 10 is excavated to form the foundation pit 12. Pouring the spread foundation: Lay the steel mesh 21 at the position of the spread foundation 20, and then pour concrete to form the spread foundation 20; Install the mooring components: Install the mooring components on the enlarged foundation 20.

[0033] In some embodiments, during the construction of the reinforced foundation block, the high-pressure jet grouting method employs a double-pipe method, with a water-cement ratio of 1.0, a grouting pressure greater than 20 MPa, a flow rate greater than 30 L / min, a drilling speed of 1 m / min, and a lifting speed of 0.1-0.2 m / min.

[0034] In some embodiments, during the construction steps of reinforcing the foundation block, such as Figure 4 As shown, the high-pressure jet grouting pile 11 has a pile diameter of 800mm and a pile spacing S of 1000mm to reduce uneven settlement. After penetrating the silt layer, the high-pressure jet grouting pile 11 enters the sandy layer to a depth of 1.0-2.5m, so that the bearing capacity of the foundation reinforced by the high-pressure jet grouting pile meets the requirements.

[0035] In some embodiments, when the mooring element is a guide bollard, in the step of pouring the enlarged foundation, after the steel mesh is laid, the lower structure of the guide bollard 30 is fixed to the steel mesh, and then concrete is poured to form the enlarged foundation 20, and the guide bollard 30 is installed; when the strength of the enlarged foundation 20 reaches the design strength, the guide bollard 30 can be used.

[0036] In some embodiments, when the mooring component is a winch 40, in the step of pouring the enlarged foundation, after the steel mesh 21 is laid, the embedded part is installed, and then concrete is poured to form the enlarged foundation 20; the winch 40 is fixed to the embedded part to realize the installation of the winch 40.

[0037] In some embodiments, after the excavation of the foundation pit 12 is completed, a 0.3m thick layer of crushed stone is first laid on the bottom surface of the foundation pit 12, and then a 0.1m thick layer of concrete is poured as a concrete cushion layer.

[0038] In some embodiments, before pouring the enlarged foundation 20, a template is erected on the upper surface of the reinforced foundation block above the foundation pit 12 to pour the enlarged foundation 20 that protrudes from the upper surface of the reinforced foundation block 10.

[0039] Example 1 In a river immersed tunnel project in Foshan City, Guangdong Province, 11 electric variable frequency winches with a capacity of 250kN and a braking load of 500kN were installed for the installation and movement of the immersed tunnel sections. Figure 5 As shown, 6 units (J1~J6) are arranged on the south bank and 5 units (J7~J11) are arranged on the north bank; 21 cable guide posts are set up, of which 15 are arranged on the south bank (D1~D15) and 6 are arranged on the north bank (D16~D21).

[0040] The installation foundations of J7, J8, J10, J11 and D16, D17, D20, and D21 located on the north bank are on a silty soft soil foundation by the river. The surface layer of this silty soft soil foundation is a silt layer, which is dark gray, saturated, soft plastic, mainly composed of clay particles, rich in organic matter, slippery to the touch, easily stains hands, has a slightly fishy smell, and contains a small amount of fine sand in some areas. Below the silt layer is a fine sand layer, which is brownish-yellow or grayish-white, saturated, medium dense, mainly composed of feldspar and quartz, with a general gradation, and contains a small amount of clay particles and medium sand.

[0041] The tides of this inland waterway are irregular semi-diurnal mixed tides, with two high tides and two low tides within a lunar day, and spring tides and neap tides within half a month, each lasting 3 days. Due to the influence of floods and storm surges during the flood season, the highest tide level generally occurs from June to September, and the lowest tide level generally occurs from December to February. The multi-year average tide level is 1.294m; the multi-year average high tide level is 1.724m; the multi-year average low tide level is 0.864m; the average tide level during the dry season is 0.934m; the average high tide level during the dry season is 1.414m; and the average low tide level during the dry season is 0.444m. In general, under silty geological conditions along riverbanks, the foundations for winches and guide posts are steel pipe pile foundations. However, steel pipe piles are expensive, and due to the shallow water along the riverbanks, pile-driving boats cannot be used for construction. Furthermore, the north bank of the river is located within a park, where roads are narrow, and mechanical equipment such as crawler cranes would cause significant damage to the park area, making steel pipe pile construction impossible. Therefore, J7, J8, J10, J11 and D16, D17, D20, D21 adopt the reinforced shore-based mooring component structure of this invention.

[0042] The reinforced mooring component structure and construction method of the present invention will be described below using J7 and D16 as examples respectively.

[0043] S1. Preparatory work: The construction positions of J7 and D16 are measured and laid out respectively. The construction position of the reinforced foundation block 10 is measured and laid out. The construction positions of J7 and D16 are leveled using a tire-mounted mini excavator. S2. Construction of reinforced foundation blocks: The double-pipe method of high-pressure jet grouting is used to reinforce the foundation at the construction locations of J7 and D16 respectively. The high-pressure jet grouting piles 11 formed are used as reinforced foundation blocks 10. The diameter of the high-pressure jet grouting piles 11 is 800mm, the pile spacing S is 1000mm, and the piles are arranged in a square. Specifically: After the pilot hole drilling rig is in place, the high-pressure water pump is turned on, the drilling speed is 1m / min, the drill rod rotates and drills downward to the designed depth. In this embodiment, the thickness of the upper silt layer is 5.8m, the pilot hole depth is 7.3m, penetrating the surface silt layer and penetrating 2.5m into the fine sand layer. The jet grouting drill bit is lowered to the bottom of the pilot hole and then rotated upwards. The grout uses ordinary Portland cement of strength grade 42.5, with a water-cement ratio of 1.0 and a cement content of not less than 450 kg / m³. The pressure of the high-pressure cement grout in the double-pipe method should be greater than 20 MPa, and the flow rate should be greater than 30 L / min. The lifting speed of the jet grouting drill bit is 0.1 m / min to 0.2 m / min. Based on the actual construction conditions, the high-pressure jet grouting pile in this embodiment is over-grown by 0.5-1.0 m. After the pile is completed, the drilling rig is moved to the next pile location.

[0044] The verticality deviation of the high-pressure jet grouting pile body shall not exceed 1%, the pile position deviation shall not exceed 50mm, and the diameter and length of the pile body shall not be less than the design value.

[0045] The reinforced foundation blocks 10 at locations J7 and D16 have been completed. The length L of the upper surface of the reinforced foundation block 10 at location J7 is 5.5m and the width D is 4.5m. The length L of the upper surface of the reinforced foundation block 10 at location D16 is 5.5m and the width D is 5.5m.

[0046] The characteristic value of the vertical bearing capacity of a single pile is 130KN, the characteristic value of the bearing capacity at the bottom of the reinforced foundation block 10 is 105KPa, and the average cubic compressive strength of the reinforced foundation block 10 is 0.8MPa; the 28-day unconfined compressive strength of the high-pressure jet grouting pile is not less than 0.8MPa.

[0047] The bearing capacity test of high-pressure jet grouting pile foundation should adopt composite foundation load test and single pile load test. It must be carried out when the pile strength meets the test load conditions and preferably 28 days after pile formation. The number of tests should be 1% of the total number of piles. For each individual project, there should be no less than 3 points for single pile and composite foundation static load test. The number of pile formation quality inspection points should be no less than 2% of the number of construction holes and no less than 6 points.

[0048] It should be noted that a process test pile must be carried out before the construction of high-pressure jet grouting piles, and the number of test piles shall not be less than three.

[0049] S3. Excavation of the foundation pit: When the strength of the high-pressure jet grouting pile reaches more than 70% of the design value, generally 5-7 days after the completion of the reinforced foundation block 10, the reinforced foundation block 10 is excavated to form the foundation pit 12. like Figures 1-2 As shown, the depth h of the foundation pit 12 at positions J7 and D16 is 1m; the foundation pit 12 at position J7 is 5m long and 4m wide; the foundation pit 12 at position D16 is 5m long and 5m wide. After the excavation of the foundation pit 12 at location J7 is completed, a 0.1m thick C20 concrete layer is poured on the bottom surface as a concrete cushion layer. The concrete cushion layer is used to increase the friction between the enlarged foundation and the reinforced foundation block, and further improve the anti-slip ability of the enlarged foundation. After the excavation of the foundation pit 12 at location D16 is completed, a 0.3m thick layer of crushed stone is laid on the bottom surface of the foundation pit 12. The crushed stone layer uses medium-coarse sand or graded crushed stone, and the coarse sand with a maximum particle size of no more than 20mm (mud content of less than 5%) is used. The crushed stone layer is used to increase the friction between the enlarged foundation 20 and the reinforced foundation block 10, and further improve the anti-sliding ability of the enlarged foundation. In other locations within the foundation pit, a 0.3m thick layer of crushed stone is first laid on the bottom surface of foundation pit 12, followed by a 0.1m thick layer of C20 concrete as a concrete cushion. The crushed stone layer and the concrete cushion are used to increase the friction between the enlarged foundation and the reinforced foundation block, thereby further improving the anti-slip capability of the enlarged foundation. S4. Casting the enlarged foundation: (e.g.) Figure 3 As shown, reinforcing bars are tied at the enlarged foundation 20 at position J7 to form three vertically spaced layers of reinforcing mesh 21 within its height range. The height of the enlarged foundation 20 at J7 is 1.6m. The first layer of reinforcing mesh is above the concrete pad, the second layer of reinforcing mesh is above the first layer of reinforcing mesh, and the interval between the second layer of reinforcing mesh and the first layer of reinforcing mesh is 0.1m. The third layer of reinforcing mesh is above the second layer of reinforcing mesh, and the interval between the second layer of reinforcing mesh and the third layer of reinforcing mesh is 1.4m. The third layer of reinforcing mesh is located close to the upper surface of the enlarged foundation 20. Since the winch 40 is installed at position J7, the parameters of the winch embedded parts must first be calculated: the enlarged foundation 20 for the winch installation uses C30 steel, and the design value of the axial compressive strength is fc = 14.3 N / mm². 2 ,like Figure 6 As shown, the winch base is embedded with four Q235 steel plates, each 550mm wide (B), 550mm high (H), and 30mm thick (t), serving as anchor plates 41. Each anchor plate 41 has nine φ32 HRB400 anchor bars 42 with a radius R of 16mm and a design tensile strength fy = 300 N / mm². 2 The spacing a of the anchor bars 42 in the shear force direction is 193mm, and the spacing b of the anchor bars 42 perpendicular to the shear force direction is 207mm. Figures 7-8 As shown, the anchor bar 42 and the anchor plate 41 are perforated and plugged together.

[0050] In this embodiment, the outermost wire rope of the J7 winch is 0.78m above the ground. The wire rope exits at any position on the drum, and the embedded parts are subjected to uneven stress. The calculation is based on the assumption that one base embedded part is subjected to uniform stress.

[0051] Given that the embedded part is subjected to a shear force V = 250 kN and a bending moment M = 250 × 0.78 = 195 kNm; the influence coefficient of the number of reinforcement layers is α. r =0.9, shear capacity coefficient of anchor bars α v =0.3, Anchor plate bending deformation reduction coefficient α b =0.83; The area of ​​the anchor bars needs to be verified, and the total cross-sectional area As of the anchor bars must simultaneously meet the following conditions: Calculate according to formulas 9.7.2-1 and 9.7.2-2 of the Code for Design of Concrete Structures (GB 50010-2010), and take the larger value: = =4281mm 2 = =5636mm 2 .

[0052] The total cross-sectional area of ​​the nine φ32 anchor bars is As = 9 × πR 2 =9×3.14×16 2 =7235mm 2 >5636mm 2 It meets the stress requirements.

[0053] Calculation of the length of anchor bar 42: The enlarged foundation 20 is formed by pouring C30 concrete, and its axial tensile strength design value is ft=1.43MPa; The shape factor α of anchor bar 42 is 0.14, and the correction factor ξa is 1.1×0.7; Winch anchor bar anchorage length I a : I a ≥ζ a I ab =ζ a ; I ab = =0.14×300×32 / 1.43=940mm, Then the anchorage length I a ≥ζ a I ab =1.1×0.7×940=724mm, anchorage length I a Take 770mm.

[0054] Calculation of anchor plate dimension 41: The thickness of the anchor plate 41 shall not be less than 60% of the diameter d of the anchor bar, and the thickness of the anchor plate of the embedded parts subjected to tension and bending shall preferably be greater than b / 8. Anchor plate thickness t=30mm≥0.6d=0.6×32=19.2mm, which meets the requirements; The anchor plate thickness t = 30mm > b / 8 = 207 / 8 = 25.9mm, which meets the requirements; The distance from the center of the anchor bar to the edge of the anchor plate is t1 = (550 - 2 × 207) / 2 = 68 > Max{2d, 20} = 64 mm, which meets the requirements; The minimum width of the anchor plate, Bmin, is 2 × 207 + 2 × 64 = 542 mm ≤ B = 550 mm, which meets the requirements. The minimum height of the anchor plate, Hmin = 2 × 193 + 2 × 64 = 514 mm ≤ H = 550 mm, meets the requirements.

[0055] When the diameter of the anchor bar is greater than 20mm, through-hole plug welding is used.

[0056] Since the upper part of the enlarged foundation 20 protrudes from the upper surface of the reinforced foundation block 10, a formwork is erected above the foundation pit 12 at the corresponding position on the upper surface of the reinforced foundation block 10, and then C30 concrete is poured to form the enlarged foundation 20 at position J7.

[0057] For the expanded base 20 at position D16, such as Figure 9 As shown, four layers of steel mesh 21 are vertically spaced within its height range. The height of the enlarged foundation 20 at position D16 is 2.0m. The first layer of steel mesh is above the concrete cushion layer. The second layer of steel mesh is above the first layer of steel mesh, with a spacing of 0.1m between the second and first layers. The third layer of steel mesh is above the second layer, with a spacing of 0.9m between the second and third layers. The fourth layer of steel mesh is above the third layer, with a spacing of 0.9m between the fourth and third layers. The fourth layer of steel mesh is located near the upper surface of the enlarged foundation 20. After the steel mesh is tied, as follows: Figure 10 As shown, φ529 is pre-embedded. A 10mm steel pipe column serves as the cable guide column 30. The cable guide column 30 is 2 meters long, with 1 meter embedded in the enlarged foundation 20 and 1 meter exposed. The cable guide column 30 is fixed to the fourth layer of steel mesh and the third layer of steel mesh, and the cable guide column 30 passes through the center of the fourth layer of steel mesh and the third layer of steel mesh.

[0058] After the cable guide post 30 is fixed, a formwork is erected above the foundation pit 12 at position D16 and at the corresponding position on the upper surface of the reinforced foundation block 10. Then, C30 concrete is poured to form the enlarged foundation 20 at position D16.

[0059] The enlarged foundation 20 uses C30 concrete with a unit weight of 23.5 kN / m³. 3 Enlarge the foundation to 20 dimensions: 5m long, 5m wide, and 2.0m high.

[0060] The pressure F acting on the bottom of the enlarged foundation 20 is 23.5 × 5 × 5 × 2.0 = 1175 kN; the compressive stress P at the bottom of the enlarged foundation 20 is F / A = 1175 / (5 × 5) = 47 kPa.

[0061] The bearing capacity safety factor of the reinforced foundation block 10 is taken as 1.3, then the required bearing capacity of the enlarged foundation 20 is 47 × 1.3 = 61 kPa; the static friction coefficient between the enlarged foundation 20 and the crushed stone layer is taken as 0.42; The maximum static friction force between the enlarged foundation 20 and the reinforced foundation block 10 is f = 1175 × 0.42 = 494 kN.

[0062] The design value for the horizontal force of D16 is 260kN.

[0063] The anti-slip stability safety factor K of the expanded foundation 20 is... =1.9 > 1.3, which meets the specification requirements.

[0064] The overturning moment of the expanded foundation 20 is M1 = 260 × (2.0 + 0.3) = 598 kN•m; where 2.0 is the height of the expanded foundation 20 and 0.3 is the thickness of the crushed stone layer. The overturning moment M2 = 1175 × 2.5 = 2938 kN•m, where 1175 is the pressure F acting on the bottom of the spread foundation 20, and 2.5 is the overturning arm. Assuming the resultant force is in the middle, the overturning arm is half the width of the spread foundation 20, i.e., 2.5m. Neglecting earth pressure, the overturning stability coefficient is 2938 / 598=4.9>1.5, which meets the specification requirements.

[0065] S5. Installing the mooring components: When installing the winch at position J7, after the expanded foundation 20 has reached the preset strength, use a truck crane to lift the winch 40, align it with the anchor plate 41, and slowly lower it. Use jacks or temporary supports at the four corners of the winch 40 base. Ensure a 5-10mm gap between the winch base and the anchor plate 41 for subsequent secondary leveling. Place adjusting shims between the winch base and anchor plate 41, and use a level to precisely adjust the level and elevation of the winch. Spot weld at the four corners of the winch base to fix the winch position. Then, check the center line and level of the winch again. After confirming that there are no errors, align the holes of the winch base with the threaded holes of the anchor plate, insert high-strength bolts, and use a torque wrench to pre-tighten symmetrically to the specified torque to complete the installation of the winch.

[0066] For the cable guide post 30 at position D16, since the cable guide post 30 has been pre-embedded in the position of the enlarged foundation 20 before the enlarged foundation 20 is poured, the cable guide post 30 can be used when the strength of the enlarged foundation 20 reaches the design strength.

[0067] Based on the above embodiments, the reinforced shore mooring assembly of the present invention is applicable to situations where the foundation of the mooring bollard or winch is located on a weak foundation on the riverbank during the inland river immersed tube relocation process. The enlarged foundation is set on a reinforced foundation block, which can prevent uneven settlement of the enlarged foundation caused by the scouring and soaking of river water. Compared with the enlarged foundation being directly poured on the soft soil foundation, the setting of the reinforced foundation block greatly improves the overturning resistance of the mooring component. The reinforced foundation block penetrates the silt layer, and some of the reinforced foundation blocks are embedded in the underlying sandy layer. The reinforced foundation block prevents the guide cable column or winch from bearing huge tension during the sinking pipe movement process, thus preventing the foundation from slipping or overturning. The reinforced foundation block of the present invention is formed by high-pressure jet grouting piles to reinforce the soft soil foundation. Compared with steel pipe piles, high-pressure jet grouting piles cause less disturbance during construction, do not require large pile driving equipment, and the jet grouting equipment is small in size, mobile and flexible, and suitable for construction on narrow inland riverbanks.

[0068] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A reinforced shore-based mooring assembly for inland river immersed tunnels, installed on a soft foundation, characterized in that, The weak foundation includes a surface silt layer and a sandy layer below the silt layer, and the shore-based mooring assembly includes: A reinforced foundation block penetrates the silt layer, and the lower part of the reinforced foundation block is embedded in the sandy layer. The reinforced foundation block has an opening facing upwards in the foundation pit. An enlarged foundation is poured into the foundation pit to form an integral structure with the reinforced foundation block, and the upper part of the enlarged foundation protrudes from the upper surface of the reinforced foundation block; at least three sets of steel mesh are provided inside the enlarged foundation, and each set of steel mesh is arranged parallel to each other and spaced apart in the vertical direction within the enlarged foundation; A mooring element, which is installed on the enlarged foundation, is used to connect to the mooring bollard on the immersed tube via a wire rope. The mooring element is a winch or a guide bollard.

2. The reinforced shore-based mooring assembly for inland river immersed tunnels according to claim 1, characterized in that, A layer of crushed stone and / or a concrete cushion layer are provided between the bottom surface of the enlarged foundation and the foundation pit. The crushed stone layer and the concrete cushion layer are used to increase the friction between the enlarged foundation and the reinforced foundation block.

3. The reinforced shore-based mooring assembly for inland river immersed tunnels according to claim 1, characterized in that, The height of the enlarged foundation is 1.5-2.0m, and the depth of the foundation pit is 1m.

4. The reinforced shore-based mooring assembly for inland river immersed tunnels according to claim 1, characterized in that, When the mooring element is a guide post, its lower end is embedded in the enlarged foundation, and its upper end extends vertically out of the enlarged foundation. The part of the guide post extending out of the enlarged foundation is used for wire rope winding.

5. The reinforced shore-based mooring assembly for inland river immersed tunnels according to claim 1, characterized in that, When the mooring element is a winch, the winch is fixed to the enlarged foundation by embedded parts.

6. The construction method for a reinforced shore-based mooring assembly for an immersed tunnel in an inland river according to any one of claims 1-5, characterized in that, Includes the following steps: Preparation: Measure and mark out the construction location of the mooring components; Construction of reinforced foundation blocks: The foundation at the construction location is reinforced using the high-pressure jet grouting method, and the resulting high-pressure jet grouting piles serve as the reinforced foundation blocks; Excavation of the foundation pit: When the strength of the high-pressure jet grouting pile reaches more than 70% of the design value, the reinforced foundation block is excavated to form the foundation pit; Pouring the spread foundation: Lay steel mesh at the construction location of the spread foundation and pour concrete to form the spread foundation; Install the mooring components: Install the mooring components on the enlarged foundation.

7. The construction method for the reinforced shore-based mooring assembly for inland river immersed tunnels according to claim 6, characterized in that, In the construction steps of the reinforced foundation block, the high-pressure jet grouting method is a double-pipe method, the water-cement ratio of the grout is 1.0, the grouting pressure is greater than 20MPa, the flow rate is greater than 30L / min, the drilling speed is 1m / min, and the lifting speed is 0.1-0.2m / min.

8. The construction method for a reinforced shore-based mooring assembly for an inland river immersed tunnel according to claim 6, characterized in that, When the mooring component is a guide bollard, in the step of pouring the enlarged foundation, after the steel mesh is laid, the lower structure of the guide bollard is fixed to the steel mesh, and then concrete is poured to form the enlarged foundation. The guide bollard is installed when the strength of the enlarged foundation reaches the design strength.

9. The construction method for a reinforced shore-based mooring assembly for an inland river immersed tunnel according to claim 6, characterized in that, When the mooring component is a winch, in the step of pouring the enlarged foundation, after the steel mesh is laid, the embedded parts are installed, and then concrete is poured to form the enlarged foundation; the winch is fixed on the embedded parts to realize the installation of the winch.

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