Row pile and suspension cable combined supporting structure for foundation pit supporting
By using a combined support structure of pile-row suspension cables on the foundation pit or slope, and using the tension prestressing of the suspension cable structure and anchor, the problems of difficulty and high cost of support construction of foundation pit or slope in the prior art are solved, and efficient and safe support effects are achieved.
Patent Information
- Application Number
- CN202421699003.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-17
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2034-07-17
AI Technical Summary
In the face of poor physical and mechanical properties of underground buried objects and soil, existing foundation pit or slope support technology has difficulty in construction and high cost. Commonly used solutions have disadvantages such as steel bars, concrete usage, high cost, large deformation, less safety redundancy, and high construction difficulty.
A combined support structure of pile suspension cables is adopted, including pile suspension, crown beam, anchor, main cable trench, main cable, sling trench and sling provided outside the foundation pit profile line. The suspension structure resists the lateral soil pressure of the foundation pit or slope, and uses the tension prestress of the anchor and main cable to control the top deformation of the support structure.
It effectively reduces the cost of foundation pit or slope support, avoids the problem of difficult construction of conventional anchor cables caused by underground buried objects, and improves construction safety and support effect through prestress control.
Smart Images
Figure CN222878716U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of foundation pit or slope support, in particular to a pile-cable combined support structure for foundation pit support. Background Art
[0002] In actual engineering, it is often necessary to support foundation pits or slopes, and the site conditions of each foundation pit or slope may be different. When vertical support is required due to site conditions, and there are unfavorable factors such as underground pipelines, existing building pile foundations, subways, etc., which result in the lack of construction anchor rods or anchor cables, or the physical and mechanical properties of the surrounding soil are very poor and cannot provide sufficient pull-out resistance, the commonly used support types for foundation pits or slopes are large-diameter cantilever piles, double-row piles, and pile rows (underground continuous walls) + internal support. Among them, the large-diameter cantilever pile scheme has the disadvantages of large steel bars and concrete consumption, high cost, insufficient constraint on top deformation, large deformation, low safety redundancy, and greater construction difficulty; the double-row piles need to occupy a large area, and there are disadvantages such as a large number of pile rows and high costs; the pile row (underground continuous wall) + internal support scheme is not conducive to earth excavation because the internal support needs to be dismantled and replaced, which is very costly. At the same time, it also has the disadvantages of great construction difficulty and long construction period.
[0003] Based on this, the present application designs a pile-row and suspension cable combined support structure to resist the lateral earth pressure of foundation pits or slopes. Compared with conventional pile-anchor schemes, it can avoid the problem of difficult construction of conventional anchor cables caused by underground buried objects; compared with double-row pile schemes or pile rows (underground continuous walls) + internal support schemes, it can greatly reduce costs. Utility Model Content
[0004] The utility model aims to solve the technical problems existing in the prior art. To this end, the utility model provides a pile-cable combined support structure to resist the lateral earth pressure of the foundation pit or slope. Compared with the conventional pile-anchor solution, it can avoid the problem that the conventional anchor cable is difficult to construct due to underground buried objects; compared with the double-row pile solution or the pile-cable (underground continuous wall) + internal support solution, it can greatly reduce the cost.
[0005] The technical solution adopted by the utility model to solve its technical problems is:
[0006] Provided is a combined support structure of pile rows and suspension cables for foundation pit support, comprising pile rows arranged outside the foundation pit outline, a crown beam arranged on the top of the pile rows, a plurality of anchors arranged outside the range affecting the foundation pit excavation depth, a parabolic or / and catenary main cable trench excavated on the foundation pit soil, a main cable laid in the main cable trench and connected to part of the anchors through a cable saddle and anchored at both ends to the anchors or / and the crown beam, a plurality of suspension cable trenches arranged between the main cable trench and the pile rows, and a plurality of suspension cables laid in the suspension cable trenches and having their two ends respectively connected to the crown beam and the main cable.
[0007] In a preferred embodiment of the utility model, the row of piles is one of rotary bored cast-in-place piles, long spiral cast-in-place piles, manually bored cast-in-place piles, steel pipe piles, steel piles, and high-strength prefabricated piles.
[0008] In a preferred embodiment of the utility model, the anchor is set at a position with the best engineering geological conditions at 2 to 3 times the excavation depth of the foundation pit. The anchor adopts one of the gravity anchor, pile foundation anchor, and anchor rod anchor, which is anchored in the rock and soil body or on the foundation.
[0009] In a preferred embodiment of the utility model, the main cable trench and the suspension cable trench adopt cast-in-place reinforced concrete structures, both of which are provided with cover plates; wherein, the width of the main cable trench is 1.0-2.0m, and the depth is 2.0-3.0m; the width of the suspension cable trench is 0.2-1.5m, and the trench bottom elevation at one end is flush with the crown beam, and the trench bottom elevation at the other end is 0.2-0.3m lower than the main cable.
[0010] In a preferred embodiment of the utility model, the vertical span ratio of the main cable is 1 / 8 to 1 / 12, and one of galvanized high-strength steel wire, galvanized steel wire rope, and galvanized steel stranded wire is selected, and its surface is also treated with anti-rust putty caulking or externally wrapped with galvanized steel wire or protective coating.
[0011] In a preferred embodiment of the utility model, one end of the sling passes through the sling hole reserved in the crown beam and is anchored by the anchor head, and the other end is connected to the main cable through a cable clamp. The length of the sling is not less than 5m, and one of galvanized steel wire rope, galvanized steel stranded wire, and galvanized high-strength parallel steel wire is selected, and its surface is treated with a hot-extruded PE protective layer or a protective coating.
[0012] In a preferred embodiment of the present utility model, the main cable is further provided with a stiffening pile at the anchoring position of the crown beam.
[0013] In a preferred embodiment of the present invention, the slings and the main cables are both tensioned with prestress.
[0014] The supporting method of the pile-cable combined supporting structure for foundation pit support is constructed according to the following steps:
[0015] Step 1: construct piles and crown beams according to design requirements;
[0016] Step 2: Construction of anchorage and main cable trench: determine the location of anchorage and main cable trench, dig the main cable trench and complete the construction of main cable trench and anchorage;
[0017] Step 3: Laying the main cable: Lay the main cable in the main cable trench, anchor both ends of the main cable to the anchorage or / crown beam, and connect the main cable to some anchorages through saddles according to the vertical span ratio requirements;
[0018] Step 4: Construction of cable trench and cable: determine the cable text, dig the cable trench and complete the construction of the cable trench, reliably connect one end of the cable to the main cable through the cable clamp, and anchor the other end through the cable hole reserved in the crown beam through the anchor head;
[0019] Step 5: Prestressing of slings and main cables: When the concrete strength of the crown beam reaches more than 75% of the design strength, the slings and main cables can be prestressed. The prestressing construction should be symmetrically tensioned in different levels. Each round is tensioned at 1 / 4 of the design tension. The order of each round is the same as the first round. After the last round of tensioning, the internal force of the key slings should be tested and fine-tuned according to the actual internal force of the slings.
[0020] Step six, excavation of foundation pit: in accordance with relevant specifications, carry out information-based construction and dynamic design, excavate in layers, monitor in time, feedback the design, and adjust the prestressing; if the support project is a temporary project, after the foundation pit is backfilled, the main cables and slings will be removed and recycled for reuse.
[0021] The support structure can also be applied to slope support structure to form a pile-cable combined support system for slope support.
[0022] Compared with the prior art, the beneficial effects of the utility model are:
[0023] The utility model adopts a suspension cable structure to resist the lateral earth pressure of the foundation pit or the slope. The suspension cable and the main cable are tension members, which can effectively exert the bearing capacity of the material. Compared with the conventional pile-anchor scheme, it can avoid the problem that the conventional anchor cable is difficult to construct due to underground buried objects. Compared with the double-row pile scheme or the row of piles (underground continuous wall) + internal support scheme, the anchor cable is used instead of the row of piles or the internal support, which greatly reduces the cost. The anchor is set on the shallow surface (pile foundation can be used when necessary), and the deformation of the top of the support structure can be controlled by tensioning prestress. The main cable and the suspension cable are located on the shallow surface, which is convenient for dismantling and recycling, and also convenient for monitoring its internal force, thereby increasing safety. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:
[0025] Figure 1 It is a plan view of the first embodiment of the pile-cable combined support structure for foundation pit support provided by the utility model;
[0026] Figure 2 It is a plan view of the second embodiment of the pile-cable combined support structure for foundation pit support provided by the utility model;
[0027] Figure 3 It is a plan layout diagram of the third embodiment of the pile-cable combined support structure for foundation pit support provided by the utility model;
[0028] Figure 4 It is a plan layout diagram of the fourth embodiment of the pile-cable combined support structure for foundation pit support provided by the utility model;
[0029] Figure 5 It is a BB cross-sectional view of a pile-and-cable combined support structure for foundation pit support in which the construction of anchor cables is restricted by underground structures in Embodiments 1 to 4;
[0030] Figure 6 It is an AA cross-sectional view of a pile-and-cable combined support structure for foundation pit support in which the construction of anchor cables is restricted by underground structures in Embodiments 1 to 4;
[0031] Figure 7 It is a BB cross-sectional view of a pile-cable combined support structure for foundation pit support in which the side wall support is mainly soft soil in Embodiments 1 to 4;
[0032] Figure 8 It is an AA cross-sectional view of a pile-cable combined support structure for foundation pit support in which the side wall support is mainly soft soil in Examples 1 to 4.
[0033] In the accompanying drawings, the components represented by the reference numerals are listed as follows:
[0034] 1—row of piles, 2—crown beam, 3—anchor, 4—main cable trench, 5—main cable, 6—sling trench, 7—sling, 8—anchor head, 9—reinforced piles, 10—pile foundation. DETAILED DESCRIPTION
[0035] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0036] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0037] In the description of the present utility model, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model; the terms "install", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0038] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.
[0039] Please refer to the instruction manual Figure 1 or attached Figure 2 or attached Figure 3 or attached Figure 4 , Attachment Figure 5 and attached Figure 6 (or attach Figure 7 and attached Figure 8 ) discloses a combined support structure of piles and cables for foundation pit support, comprising a pile row 1 arranged outside the foundation pit outline, a crown beam 2 arranged on the top of the pile row, a plurality of anchors 3 arranged outside the range of the depth affecting the foundation pit excavation, a parabolic or / and catenary main cable trench 4 excavated on the foundation pit soil, a main cable 5 laid in the main cable trench and connected to part of the anchors through a saddle and anchored at both ends to the anchors or / and the crown beam, a plurality of suspension cable trenches 6 arranged between the main cable trench and the pile row, and a plurality of suspension cables 7 laid in the suspension cable trench and connected to the crown beam and the main cable at both ends. This embodiment uses a suspension cable structure to resist the lateral soil pressure of the foundation pit, and the suspension cables and main cables are load-bearing components, which can effectively exert the bearing capacity of the material.
[0040] The pile row 1 in this embodiment serves as a direct retaining member, with its bottom embedded in the rock mass at the bottom of the foundation pit and its top connected into a whole by a cap beam 2. The pile row can be one of rotary bored cast-in-place piles, long spiral cast-in-place piles, manually dug bored cast-in-place piles, steel pipe piles, steel piles, and high-strength prefabricated piles.
[0041] Preferably, the anchor 3 is set at a position with the best engineering geological conditions of 2 to 3 times the excavation depth of the foundation pit, and can be anchored in the rock and soil body or on the foundation by one of gravity anchor, pile foundation anchor and anchor rod anchor. Among them, the gravity anchor is generally used for a small span (less than 20 to 30m). When the physical and mechanical properties of the bottom bearing layer and the side wall rock and soil layer of the anchor are poor, the pile foundation 10 or the foundation reinforcement treatment can be used, such as the attached Figure 8 shown.
[0042] Preferably, the main cable trench 4 and the suspension cable trench 6 adopt cast-in-place reinforced concrete structures, both of which are provided with cover plates; wherein, the width of the main cable trench 4 is 1.0-2.0m, and the depth is 2.0-3.0m; the width of the suspension cable trench 6 is 0.2-1.5m, and the trench bottom elevation at one end is flush with the crown beam, and the trench bottom elevation at the other end is 0.2-0.3m lower than the main cable.
[0043] Preferably, the vertical span ratio of the main cable 5 is 1 / 8 to 1 / 12, and one of galvanized high-strength steel wire, galvanized steel wire rope, and galvanized steel strand is selected, and its surface is also treated with rust-proof putty caulking or externally wrapped with galvanized steel wire or protective coating (such as manganese phosphating wear-resistant protective coating). When galvanized steel wire rope is selected, a large-twist closed steel wire rope is preferably selected. In order to facilitate the tensioning of the main cable, jacks are arranged at both ends of the main cable for tensioning, and the main cable is ensured to be formed through the cable tightening process.
[0044] Preferably, one end of the sling 7 passes through the sling hole reserved in the crown beam 2 (the sling hole is set in the middle position between two piles of the pile row) and is anchored by the anchor head 8 (the function of the anchor head is to tension and lock the prestress), and the other end is connected to the main cable through a cable clamp, and the sling is tensioned with prestress through the anchor head end. The length of the sling 7 is not less than 5m, and one of galvanized steel wire rope, galvanized steel strand, and galvanized high-strength parallel steel wire is selected, and its surface is treated with a hot-extruded PE protective layer or a protective coating (such as: manganese phosphating wear-resistant protective coating).
[0045] Preferably, considering that the stress at the connection portion between the main cable and the crown beam is very large, a reinforcing pile 9 is added at the anchoring position of the main cable and the crown beam.
[0046] The supporting method of the supporting structure is constructed according to the following steps:
[0047] Step 1: construct piles and crown beams according to design requirements;
[0048] Step 2: Construction of anchorage and main cable trench: determine the location of anchorage and main cable trench, dig the main cable trench and complete the construction of main cable trench and anchorage;
[0049] Step 3: Laying the main cable: Lay the main cable in the main cable trench, anchor both ends of the main cable to the anchorage or / crown beam, and connect the main cable to some anchorages through saddles according to the vertical span ratio requirements;
[0050] Step 4: Construction of cable trench and cable: determine the cable text, dig the cable trench and complete the construction of the cable trench, reliably connect one end of the cable to the main cable through the cable clamp, and anchor the other end through the cable hole reserved in the crown beam through the anchor head;
[0051] Step 5: Prestressing of slings and main cables: When the concrete strength of the crown beam reaches more than 75% of the design strength, the slings and main cables can be prestressed. The prestressing construction should be symmetrically tensioned in different levels. Each round is tensioned at 1 / 4 of the design tension. The order of each round is the same as the first round. After the last round of tensioning, the internal force of the key slings should be tested and fine-tuned according to the actual internal force of the slings.
[0052] Step six, excavation of foundation pit: in accordance with relevant specifications, carry out information-based construction and dynamic design, excavate in layers, monitor in time, feedback the design, and adjust the prestressing; if the support project is a temporary project, after the foundation pit is backfilled, the main cables and slings will be removed and recycled for reuse.
[0053] According to the pile-cable combined support structure for foundation pit support disclosed in the utility model, the following specific embodiments are provided:
[0054] Embodiment 1
[0055] As attached Figure 1 , Attachment Figure 5 or attached Figure 7 As shown, a relatively regular square foundation pit is provided with four anchors outside the four corner points. The anchors should be located on the extended lines of the diagonals. The internal force of the slings should adopt a spatial analysis model. One pile and one sling should be used in the middle of the side wall of the foundation pit. The internal force at the corners of the foundation pit is small, and the spacing between the slings can be appropriately enlarged.
[0056] Embodiment 2
[0057] As attached Figure 2 , Attachment Figure 5 To Attachment Figure 8 As shown in the figure, when only one side of the foundation pit does not meet the conditions for adopting the conventional pile-anchor scheme, and the length of the foundation pit on this side is relatively large (generally the span is greater than 60-100m), self-anchoring at both ends (i.e. the main cable is connected to the crown beam) + two (or more) anchors can be used, similar to a three-span suspension bridge. Considering that the stress at the connection between the main cable and the crown beam is very large, a stiffening pile is added there.
[0058] Embodiment 3
[0059] As attached Figure 3 , Attachment Figure 5 or attached Figure 7 As shown, when the conditions for adopting conventional pile-anchor scheme are not met on the adjacent sides of the foundation pit and the lengths of the adjacent sides are similar, three corner points can be used to set anchors and a cable saddle can be set at the middle anchor.
[0060] Embodiment 4
[0061] As attached Figure 4 , Attachment Figure 5 To Attachment Figure 8 As shown in the figure, when the adjacent two sides of the foundation pit do not meet the conditions for adopting the conventional pile anchor scheme, and the length difference between the adjacent two sides is large, self-anchoring can be adopted at the outer end point of the long side (i.e. the connection between the main cable and the crown beam) + two anchors can be set at the corner point + one anchor near the point where the long side is divided into three equal parts, and a cable saddle can be set at the middle anchor. Considering that the stress at the self-anchor part (the connection part between the main cable and the crown beam) is very large, a stiffening pile is added there.
[0062] The above-mentioned pile-cable combined support structure can also be applied to slope support structures to form a pile-cable combined support system for slope support.
[0063] It is worth noting that the pile-cable combined supporting structure for foundation pit support provided by the utility model can also be combined with other foundation pit support forms, such as pile-cable combined structure + diagonal bracing or angle bracing, pile-cable combined structure + fixed foot anchor rods (anchor cables), pile-cable combined structure + active zone reinforcement, and pile-cable combined structure + passive zone reinforcement.
[0064] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.
Claims
1. A pile-cable combined support structure for foundation pit support, comprising a pile row arranged outside the foundation pit outline and a cap beam arranged on the top of the pile row; characterized in that: It also includes multiple anchors located outside the range that affects the depth of foundation pit excavation, a parabolic and / or catenary main cable trench excavated on the foundation pit soil, a main cable laid in the main cable trench and connected to part of the anchors through saddles and anchored at both ends to the anchors and / or the crown beam, a number of suspension cable trenches located between the main cable trench and the pile row, and a number of suspension cables laid in the suspension cable trench with the two ends respectively connected to the crown beam and the main cable.
2. The support structure according to claim 1, characterized in that: The row of piles is one of rotary bored cast-in-place piles, long spiral cast-in-place piles, manually bored cast-in-place piles, steel pipe piles, steel piles, and high-strength prefabricated piles.
3. The support structure according to claim 1, characterized in that: The anchor is set at a position with the best engineering geological conditions at 2 to 3 times the excavation depth of the foundation pit. The anchor adopts one of the gravity anchor, pile foundation anchor and anchor rod anchor, and is anchored in the rock and soil body or on the foundation.
4. The support structure according to claim 1, characterized in that: The main cable trench and suspension cable trench adopt cast-in-place reinforced concrete structure, both of which are provided with cover plates; wherein: The width of the main cable trench is 1.0-2.0m, and the depth is 2.0-3.0m; The width of the suspension cable trench is 0.2-1.5m, the trench bottom elevation at one end is flush with the crown beam, and the trench bottom elevation at the other end is 0.2-0.3m lower than the main cable.
5. The supporting structure according to claim 1, characterized in that: The vertical span ratio of the main cable is 1 / 8 to 1 / 12, and one of galvanized high-strength steel wire, galvanized steel wire rope and galvanized steel strand is selected.
6. The supporting structure according to claim 5, characterized in that: The surface of the main cable is also treated with anti-rust putty caulking or externally wrapped with galvanized steel wire or protective coating.
7. The support structure according to claim 1, characterized in that: One end of the sling passes through the sling hole reserved in the crown beam and is anchored by the anchor head, and the other end is connected to the main cable through a cable clamp. The length of the sling is not less than 5m, and one of galvanized steel wire rope, galvanized steel stranded wire, and galvanized high-strength parallel steel wire is selected.
8. The support structure according to claim 7, characterized in that: The surface of the sling is treated with a hot-extruded PE protective layer or a protective coating.
9. The supporting structure according to claim 1, characterized in that: The main cable is also provided with a reinforcing pile at the anchoring position of the crown beam.
10. The supporting structure according to claim 1, characterized in that: The slings and main cables are both tensioned with prestress.