Large deep foundation pit supporting system

Abstract

The utility model provides a large deep foundation pit supporting system which comprises supporting piles arranged on the periphery of a foundation pit, waist beam structures are fixed in the height direction of the inner side walls of the supporting piles, anchor cables are connected to the waist beam structures, and the anchor cables are anchored in a peripheral foundation of the foundation pit. A foundation pit bottom sealing layer is fixed to the inner bottom of the foundation pit through anti-floating piles, and a structural foundation layer is arranged on the top of the foundation pit bottom sealing layer. Cap beams are arranged at the tops of the supporting piles, intercepting ditches are arranged on the peripheries of the tops of the cap beams, apron slopes are arranged on the peripheries of the intercepting ditches, and waterproof curtains are arranged on the peripheries of the apron slopes and extend into the foundation on the periphery of the foundation pit. An inter-pile protection plate is arranged between every two adjacent supporting piles and anchored in the peripheral foundation through a reinforcing anchor rod. The supporting system is high in waterproofness and good in stability, can meet the requirement for small deformation of the foundation pit when facing the foundation pit of the strong permeable stratum, and meanwhile can guarantee safe operation in the foundation pit for a long time.

Description

Technical Field

[0001] The utility model relates to the technical field of underground engineering, in particular to a large deep foundation pit support system. Background Art

[0002] At present, it is often necessary to excavate foundation pits in urban reconstruction and construction. Most foundation pit excavation and support adopt steel sheet pile cofferdams, steel structure cofferdams or slope excavation. Due to the characteristics of some foundation pit excavation depths and large foundation pit sizes, adjacent structures and abundant groundwater, it is necessary to use larger cross-section steel or larger slope width to meet the foundation pit stability requirements. Common steel sheet pile cofferdams or slope excavation have the following three disadvantages: First, slope excavation occupies a large area and is not suitable for cities or sites with adjacent structures. Its use is greatly restricted by the site; second, the use of steel sheet piles or steel cofferdam structures requires a large amount of steel and internal supports. The excessive number of internal supports affects the efficiency of excavation operations and the workload of demolition is large. Especially when constructing in groundwater-rich strata, it is necessary to increase the depth or increase the profile type to resist the force of groundwater. In order to ensure the smooth excavation of large deep foundation pits and reduce the difficulty and safety risks of foundation pit support construction, it is necessary to improve the foundation pit support system and construction methods. Utility Model Content

[0003] In order to solve the problems existing in the above-mentioned background technology and ensure the problem of safe operation in the foundation pit for a long time, a large deep foundation pit support system is provided. The support system has strong waterproofness and good stability. When facing the foundation pit in highly permeable strata, the support system can meet the demand for small deformation of the foundation pit and at the same time ensure the problem of safe operation in the foundation pit for a long time.

[0004] In order to realize the above-mentioned technical features, the purpose of the utility model is achieved as follows: a large-scale deep foundation pit support system, including supporting piles arranged on the periphery of the foundation pit, a waist beam structure is fixed along the height direction of the inner wall of the supporting piles, and an anchor cable is connected to the waist beam structure, and the anchor cable is anchored inside the outer foundation of the foundation pit; the inner bottom of the foundation pit is fixed with a foundation pit bottom sealing layer by anti-floating piles, and the top of the foundation pit bottom sealing layer is provided with a structural foundation layer; a cap beam is provided on the top of the supporting pile, a drainage ditch is provided on the periphery of the top of the cap beam, a drainage slope is provided on the periphery of the drainage ditch, and a water-stop curtain is provided on the periphery of the drainage slope and extends into the inner periphery of the foundation pit foundation foundation; pile protection plates are provided between adjacent supporting piles, and the pile protection plates are anchored inside the outer foundation by reinforcing anchor rods.

[0005] The waist beam structure includes a first waist beam, a second waist beam and a third waist beam which are arranged laterally from top to bottom along the supporting piles. The first waist beam, the second waist beam and the third waist beam are respectively anchored to the outer foundation of the foundation pit through multiple groups of anchor cables; the anchor cables are fixed to the corresponding first waist beam, the second waist beam and the third waist beam through the anchor cable sealing structure.

[0006] A drainage ditch is arranged at the periphery of the closed layer at the bottom of the foundation pit, and a water collection well is arranged at the top corner of the drainage ditch.

[0007] The top surface of the cap beam is higher than the original ground by a certain distance.

[0008] A protective railing is arranged on the periphery of the water dispersion slope.

[0009] The diameter of the supporting piles is d, and the distance between adjacent supporting piles is S, where S>d.

[0010] The inter-pile protection plate is connected with the supporting piles to form an integral protection structure, and constitutes a closed and complete inner layer water-stopping curtain.

[0011] The area of ​​the sealing layer at the bottom of the foundation pit is greater than or equal to the bottom area of ​​the foundation pit;

[0012] A building is arranged on top of the structural base layer.

[0013] The depth of the foundation pit is more than 10m;

[0014] The foundation pit is located in a water-rich area, and the stratum has strong water permeability;

[0015] The surface water content at the designed depth of the foundation pit is high.

[0016] The utility model has the following beneficial effects:

[0017] 1. The support system of the utility model has strong waterproofness and good stability. When facing the foundation pit in highly permeable strata, the support system can meet the demand for small deformation of the foundation pit and at the same time ensure the problem of safe operation in the foundation pit for a long time.

[0018] 2. The utility model adopts water-stop curtains on the walls around the foundation pit and anti-floating piles and concrete bottom slabs on the bottom of the foundation pit to form a complete water-stop system. The anti-floating piles prevent groundwater from entering the foundation pit through capillaries, greatly reducing the amount of groundwater entering the foundation pit. The concrete bottom slab blocks the passage between the foundation pit and the groundwater.

[0019] 3. The supporting piles on the surrounding walls of the foundation pit of the utility model and the protective plates between the piles form a closed and complete inner waterproof curtain. The combined effect of the waterproof pile layer and the sealing layer at the bottom of the foundation pit effectively prevents groundwater from entering the foundation pit, avoiding the problem of surrounding foundation settlement caused by foundation pit drainage.

[0020] 4. The intercepting ditch and drainage slope on the top of the foundation pit of the utility model can effectively prevent ground water from entering the foundation pit. Auxiliary drainage facilities such as drainage ditches and water collection wells are arranged in the closed layer at the bottom of the foundation pit to ensure a good construction environment during the construction of the foundation pit.

[0021] 5. The utility model effectively blocks the soil pressure around the foundation pit through the arrangement of a water-stop curtain layer, supporting piles, anchor cables, reinforced anchor rods and protection between piles, thereby ensuring good integrity and stability of the deep foundation pit. When faced with complex deep foundation pit construction environments such as highly permeable strata and nearby large structures, the support system can meet the demand for small foundation pit deformation and ensure safe operation in the foundation pit for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0023] Figure 1 It is a cross-sectional schematic diagram of the utility model.

[0024] Figure 2 It is a schematic diagram of the plan layout of the utility model.

[0025] Figure 3 This is a schematic diagram of the side wall protection of the utility model.

[0026] Figure 4 It is a schematic diagram of the supporting piles and the protective structure between the piles of the utility model.

[0027] Figure 5 This is the construction status diagram of the drainage slope, intercepting ditch, water-stop curtain and supporting piles during the construction process of this project.

[0028] Figure 6 This is the construction status diagram of the first layer excavation during the construction process of this project.

[0029] Figure 7 This is a construction status diagram of the first waist beam during the construction process of this project.

[0030] Figure 8 This is the construction status diagram of the first layer of central soil excavation during the construction process of this project.

[0031] Fig. 9 This is the construction status diagram of the second layer excavation during the construction process of this project.

[0032] Fig.10 This is a diagram showing the construction status of the second waist beam during the construction process of this project.

[0033] Fig.11 This is the construction status diagram of the excavation of the second layer of central soil during the construction process of this project.

[0034] Fig.12 This is the construction status diagram of the third layer excavation during the construction process of this project.

[0035] Fig.13 This is a construction status diagram of the third waist beam during the construction process of this project.

[0036] Fig.14 This is the construction status diagram of the excavation of the third layer of central soil during the construction process of this project.

[0037] Fig.15 This is the construction status diagram of anti-floating piles during the construction process of this project.

[0038] Fig.16 This is the construction status diagram of the foundation pit bottom sealing layer, structural foundation layer, drainage ditch and collection well during the construction process of this project.

[0039] In the figure: water-stop curtain 1, guardrail 2, drainage slope 3, intercepting ditch 4, cap beam 5, first waist beam 6, supporting pile 7, anchor cable 8, second waist beam 9, third waist beam 11, drainage ditch 12, building 13, structural foundation layer 14, foundation pit bottom sealing layer 15, anti-floating pile 16, water collection well 17, cable end sealing structure 18, inter-pile protection plate 19, reinforcing anchor rod 20, first waist beam mounting groove 21, central soil 22, second waist beam mounting groove 23, third waist beam mounting groove 24. DETAILED DESCRIPTION

[0040] The implementation modes of the present utility model are further described below in conjunction with the accompanying drawings.

[0041] Embodiment 1:

[0042] See also Figure 1-4 A large deep foundation pit support system includes support piles 7 arranged at the periphery of the foundation pit, a waist beam structure is fixed along the height direction of the inner wall of the support pile 7, an anchor cable 8 is connected to the waist beam structure, and the anchor cable 8 is anchored inside the periphery of the foundation pit; the inner bottom of the foundation pit is fixed with a foundation pit bottom sealing layer 15 through an anti-floating pile 16, and a structural foundation layer 14 is arranged on the top of the foundation pit bottom sealing layer 15; a cap beam 5 is arranged on the top of the support pile 7, a water interception ditch 4 is arranged on the periphery of the top of the cap beam 5, a water dispersion slope 3 is arranged on the periphery of the water interception ditch 4, and a water-stop curtain 1 is arranged on the periphery of the water dispersion slope 3 and extends into the periphery of the foundation pit foundation; an inter-pile protection plate 19 is arranged between adjacent support piles 7, and the inter-pile protection plate 19 is anchored inside the periphery foundation through a reinforcing anchor rod 20. The support system has strong waterproofness and good stability. When facing a foundation pit with a strong permeable stratum, the support system can meet the demand for small deformation of the foundation pit and ensure the problem of long-term safe operation in the foundation pit.

[0043] Furthermore, the waist beam structure includes a first waist beam 6, a second waist beam 9 and a third waist beam 11 which are arranged transversely from top to bottom along the support pile 7, and the first waist beam 6, the second waist beam 9 and the third waist beam 11 are respectively anchored to the peripheral foundation of the foundation pit through multiple groups of anchor cables 8; the anchor cables 8 are fixed to the corresponding first waist beam 6, the second waist beam 9 and the third waist beam 11 through the anchor cable end capping structure 18. By using the first waist beam 6, the second waist beam 9 and the third waist beam 11 at different height layers, the support pile 7 can be anchored in the height direction, thereby ensuring that the support pile 7 can withstand the extrusion of the soil outside the foundation pit, and effectively enhancing the stability and reliability of its support.

[0044] Furthermore, a drainage ditch 12 is arranged at the periphery of the foundation pit bottom sealing layer 15, and a water collection well 17 is arranged at the top corner of the drainage ditch 12. The drainage ditch 12 can facilitate the subsequent collection of water inside the foundation pit, so as to facilitate the subsequent collection of water inside the foundation pit for centralized discharge.

[0045] Furthermore, the top surface of the cap beam 5 is a certain distance above the original ground. The cap beam 5 can facilitate the fixation of the top of the entire support pile 7 to enhance the integrity of the entire support pile 7, thereby enhancing the subsequent support reliability and stability of the support pile 7 to the foundation pit.

[0046] Furthermore, a guardrail 2 is provided on the periphery of the water-spreading slope 3. The guardrail 2 can effectively protect the construction area, thereby ensuring the safety of the construction process.

[0047] Furthermore, the diameter of the support piles 7 is d, and the distance between adjacent support piles 7 is S, where S>d. By adopting the above-mentioned size arrangement, the convenience and reliability of the subsequent construction of the support piles 7 are guaranteed.

[0048] Furthermore, the inter-pile protection plate 19 is connected with the supporting piles 7 to form an integral protection structure, and forms a closed and complete inner waterproof curtain. The inner waterproof curtain achieves the purpose of reliable waterproofing of the foundation pit.

[0049] Furthermore, the area of ​​the foundation pit bottom sealing layer 15 is greater than or equal to the bottom area of ​​the foundation pit. Through the above-mentioned area size matching, reliable waterproofing of the foundation pit bottom is guaranteed.

[0050] Furthermore, a building 13 is arranged on the top of the structural foundation layer 14. Through the arrangement and installation of the above-mentioned building 13, the reliability and stability of the support and installation of the building 13 can be enhanced.

[0051] Furthermore, the depth of the foundation pit is more than 10m, thereby being able to enhance the adaptability range.

[0052] Furthermore, the foundation pit is located in a water-rich area, and the stratum has strong water permeability, thereby ensuring that the foundation pit can adapt to the water-rich environment and enhancing its adaptability.

[0053] Furthermore, the surface water content at the designed depth of the foundation pit is high.

[0054] Furthermore, the bottom plate of the structure in the foundation pit has a high requirement for anti-floating property. Based on this, the fixing reliability of the sealing layer 15 at the bottom of the foundation pit is enhanced by setting the anti-floating piles 16 .

[0055] Embodiment 2:

[0056] See also Figure 5-16 , a construction method of a large deep foundation pit support system, comprising the following steps:

[0057] Step 1: Before construction, mark the location of the foundation pit and construct protective railings to ensure that the construction within the foundation pit is in a closed state;

[0058] Step 2, constructing the water dispersion slope 3 and the intercepting ditch 4;

[0059] Step 3, sequentially construct the water-stop curtain 1 and support piles 7 around the foundation pit;

[0060] Step 4, pouring a reinforced concrete cap beam 5 on the top of the support pile 7;

[0061] Step 5, after the cap beam 5 is constructed, the foundation pit is excavated. The foundation pit excavation should be carried out in layers and sections. The first layer of excavation depth is to the bottom elevation of the first waist beam 6 of the first layer of anchor cables. First, the first waist beam installation groove 21 is formed along the inner wall of the support pile 7 in a circular direction, and the central soil 22 is reserved. After the excavation is completed, the first waist beam 6 and the anchor cable 8 are installed. After the anchor cable 8 is tensioned, the anchor is sealed, and the reinforcing anchor rod 20 and the pile protection plate 19 are installed, and the central soil 22 is excavated;

[0062] Step 6, excavate the second layer, the second layer is excavated to the bottom elevation of the second waist beam 9 of the second anchor cable, the excavation method is the same as the first layer construction, firstly excavate in a circular direction to form the second waist beam installation groove 23, apply the second anchor cable, the second waist beam 9 and the anchor end closure, strengthen the anchor rod 20 and the pile protection plate 19, and then excavate the central soil;

[0063] Step 7, excavate the third layer, the third layer is excavated to the bottom elevation of the third waist beam 11 of the third anchor cable, the excavation method is the same as the second layer construction, firstly excavate in a circular direction to form the third waist beam installation groove 24, and then construct the third anchor cable, the third waist beam 11, the anchor end sealing, the reinforcement anchor rod 20 and the pile protection plate 19, and then excavate the central soil;

[0064] Step 8, finally excavate the next layer of soil. After excavating to the top elevation of the anti-floating piles 16, install the anti-floating piles 16, and then pour the foundation pit bottom sealing layer 15, drainage ditch 12 and collection well 17 in sequence. The entire foundation pit excavation and support construction is completed.

Claims

1. A large deep foundation pit support system, characterized in that: The invention comprises support piles (7) arranged at the periphery of a foundation pit, a waist beam structure being fixed along the height direction of the inner wall of the support piles (7), an anchor cable (8) being connected to the waist beam structure, and the anchor cable (8) being anchored inside the periphery foundation of the foundation pit; a foundation pit bottom sealing layer (15) being fixed to the inner bottom of the foundation pit via anti-floating piles (16), and a structural foundation layer (14) being arranged on the top of the foundation pit bottom sealing layer (15); a cap beam (5) being arranged on the top of the support piles (7), a water intercepting ditch (4) being arranged on the periphery of the top of the cap beam (5), a water dispersion slope (3) being arranged on the periphery of the water intercepting ditch (4), and a water stop curtain (1) being arranged on the periphery of the water dispersion slope (3) and extending into the periphery foundation of the foundation pit; and an inter-pile protection plate (19) being arranged between adjacent support piles (7), and the inter-pile protection plate (19) being anchored inside the periphery foundation via a reinforcing anchor rod (20).

2. A large deep foundation pit support system according to claim 1, characterized in that: The waist beam structure comprises a first waist beam (6), a second waist beam (9) and a third waist beam (11) which are arranged transversely in sequence from top to bottom along the support pile (7); the first waist beam (6), the second waist beam (9) and the third waist beam (11) are respectively anchored to the peripheral foundation of the foundation pit through a plurality of groups of anchor cables (8); the anchor cables (8) are fixed to the corresponding first waist beam (6), the second waist beam (9) and the third waist beam (11) through an anchor cable end capping structure (18).

3. A large deep foundation pit support system according to claim 1, characterized in that: A drainage ditch (12) is arranged at the periphery of the sealing layer (15) at the bottom of the foundation pit, and a water collection well (17) is arranged at the top corner of the drainage ditch (12).

4. A large deep foundation pit support system according to claim 1, characterized in that: The top surface of the cap beam (5) is higher than the original ground by a certain distance.

5. A large deep foundation pit support system according to claim 1, characterized in that: A protective railing (2) is arranged on the periphery of the water dispersion slope (3).

6. A large deep foundation pit support system according to claim 1, characterized in that: The diameter of the support pile (7) is d, and the distance between adjacent support piles (7) is S, where S>d.

7. A large deep foundation pit support system according to claim 1, characterized in that: The inter-pile protection plate (19) is connected to the support piles (7) to form an integral protection structure and to form a closed and complete inner waterproof curtain.

8. A large deep foundation pit support system according to claim 1, characterized in that: The area of ​​the foundation pit bottom sealing layer (15) is greater than or equal to the bottom area of ​​the foundation pit; A building (13) is arranged on top of the structural base layer (14).

9. A large deep foundation pit support system according to claim 1, characterized in that: The depth of the foundation pit is above 10m.

10. A large deep foundation pit support system according to claim 1, characterized in that: The foundation pit is located in a water-rich area, and the stratum has strong water permeability; The surface water content at the designed depth of the foundation pit is high.

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