A self-stable assembly type supporting structure and a construction method thereof

Abstract

The embodiment of the application discloses a self-stabilizing assembly type supporting structure and a construction method thereof, comprising a supporting system of a cement-soil wall, characterized in that horizontal section steel is spliced at the bottom of vertical section steel to form a "⊥" type combined structure, and is fixed by welding of inclined steel. The cement-soil wall is a foundation pit supporting wall, and the supporting system is a combined steel structure inserted into the cement-soil wall. The structure construction comprises the following construction steps: cement-soil wall construction, steel combined structure assembly, wall bottom construction high-pressure jet grouting pile, insertion of the steel combined structure and rotation of 90 degrees. The structure has good self-stabilizing capacity, can effectively prevent excessive displacement of the soil at the bottom of the foundation pit and the phenomenon of kick damage of the enclosing wall, and ensures the overall safety of the foundation pit.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of foundation pit retaining, and particularly to a self-stabilizing assembled support structure and a construction method thereof. Background Art

[0002] Foundation pit support is a temporary measure used to support, reinforce, protect, and control groundwater in foundation pits, protecting the main underground structure of a building and ensuring the safety of the surrounding environment. Currently, cement-soil mixing piles / H-beam supports inserted into the wall are commonly used for deep foundation pits. However, if the pit bottom soil has a low compression modulus, low shear strength, or is overloaded, the retaining wall skirtings can significantly deform, leading to instability of the entire foundation pit and jeopardizing its safety. Summary of the Invention

[0003] The purpose of the present invention is to provide a self-stabilizing assembled support structure and a construction method thereof. The structure has good self-stabilizing ability, can effectively prevent the soil at the bottom of the foundation pit from displacing too much and the retaining wall from being damaged by kicking, thereby ensuring the overall safety of the foundation pit.

[0004] An embodiment of the present invention provides a self-stabilizing assembled support structure, comprising: a cement soil wall and a plurality of combined steel sections;

[0005] A plurality of the combined steel sections are inserted into the cement soil wall;

[0006] The combined steel includes: horizontal steel, vertical steel, and multiple oblique steels;

[0007] The transverse section steel is located at the bottom of the vertical section steel, and the vertical section steel is perpendicular to the transverse section steel, and the transverse section steel and the vertical section steel form a "⊥"-shaped structure;

[0008] One end of the plurality of inclined steels is fixed on the transverse section steel, and the other end is fixed on the vertical section steel, and the inclined steel is used to support the transverse section steel and the vertical section steel;

[0009] The transverse steel sections, vertical steel sections and a plurality of oblique steel sections constitute a combined steel structure.

[0010] The combined steel sections of the "⊥"-shaped structure offer high stability and enhance the shear and overturning resistance of the supporting structure, providing a certain level of strength and rigidity. Two diagonal steel sections are added at the bottom to provide support between the vertical and horizontal sections.

[0011] In a feasible solution, the vertical steel sections of the self-stabilizing assembled support structure are H-shaped steel sections, and the transverse steel sections are H-shaped steel sections.

[0012] H-shaped steel is an economic section high-efficiency section bar with more optimized section area distribution and more reasonable strength, and has the advantages of bending resistance, simple construction, cost saving and light structure weight. Because the section size of the I-shaped steel is relatively high and narrow, the inertia moments of the two main axes of the section are relatively large, and the I-shaped steel can be directly used for the member subjected to bending in the plane of the web or combined into a lattice type stressed member.

[0013] In a feasible scheme, the transverse section steel, the vertical section steel and the inclined steel of the self-stable assembly type supporting structure are fixed by welding.

[0014] Welding is a manufacturing process and technology that combines metal or other thermoplastic materials such as plastic by heating, high temperature or high pressure. The surface of the transverse section steel, the vertical section steel and the inclined steel is fused together by welding, which increases the stability of the three.

[0015] The embodiment of the application provides a construction method of a self-stable assembly type supporting structure, which comprises the following steps:

[0016] S10, constructing a cement-soil wall;

[0017] S20, using a high-pressure rotary jet pile construction device to drill and jet a high-pressure rotary jet pile with a preset width and depth at the bottom of the cement-soil wall;

[0018] S30, inserting a plurality of combined section steel structures into the cement-soil wall at a preset distance and rotating 90 degrees before the cement-soil mixture is hardened.

[0019] The cement-soil wall plays a role of resisting the lateral stress of the surrounding soil, the combined section steel structure is inserted into the cement-soil pile / wall, mainly plays a role of retaining soil and resisting shear, the combined section steel structure is inserted as stress reinforcement before the cement-soil wall is hardened, and after the cement is hardened, a continuous, complete and jointless underground wall body with high strength and rigidity is formed.

[0020] In a feasible scheme, the S10 of the construction method of the foundation pit enclosure structure specifically comprises the following steps:

[0021] S101, determining related parameters such as cement-soil mixing pile / wall construction technology, mixing sinking and lifting speed, cement mixing amount and mixing ratio before construction.

[0022] The related parameters are determined to prepare for the construction.

[0023] In a feasible scheme, the S20 of the construction method of the foundation pit enclosure structure specifically comprises the following steps:

[0024] S201, presetting construction parameters such as drilling rotation and lifting speed of the high-pressure rotary jet pile machine, air pressure and jet grouting.

[0025] S202. Preset the amount of cement slurry sprayed when the high-pressure jet pile driver rotates and lifts.

[0026] In order to avoid leakage, excessive deformation and ground subsidence if the cement content in cement soil is insufficient or different soil layers are not treated differently.

[0027] In a feasible solution, the S30 of the construction method of the foundation pit retaining structure specifically includes the following steps:

[0028] S301. Apply drag reducing agent on the surface of the composite steel structure;

[0029] S302. Adjust the verticality of the steel structure during the process of inserting the combined steel structure.

[0030] Only by controlling the verticality of the steel section can the mechanical properties of the cement soil wall and the steel section structure be fully utilized, thereby ensuring the anti-overturning ability of the support structure.

[0031] In a feasible solution, the construction method of the foundation pit retaining structure further includes:

[0032] S40, digging foundation pit;

[0033] S50. Construction of underground structures between foundation pit retaining structures;

[0034] S60. Backfill earth between the foundation pit retaining structure and the underground structure.

[0035] This self-stabilizing assembled support structure can ensure the overall stability of the foundation pit, increase the shear resistance of the support structure and prevent kicking damage, thereby ensuring the safety of the entire foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0037] Figure 1 A schematic diagram of a combined steel structure in an embodiment of the present invention;

[0038] Figure 2 A diagram showing the rotation state of a combined steel structure according to an embodiment of the present invention;

[0039] Figure 3 A diagram showing the state of a combined steel structure in a cement-soil wall according to an embodiment of the present invention;

[0040] Figure 4 Schematic diagram of the overall structure of an embodiment of the present invention.

[0041] Numbers in the figure:

[0042] 1. Vertical steel; 2. Horizontal steel; 3. Diagonal steel; 4. Cement-soil wall; 5. High-pressure jet grouting piles; 6. Underground structure. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0044] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 should not be understood as limiting the present invention.

[0045] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0046] At present, the H-shaped steel support inserted into the cement soil wall 4 is a commonly used support structure for deep foundation pit support. However, if the compression modulus of the pit bottom soil is low, the shear strength is low, or there is overload outside the pit, it will cause a large deformation of the retaining wall skirting, thereby causing the entire foundation pit to become unstable and endangering the safety of the foundation pit.

[0047] The cement-soil wall 4 in the present invention has an inserted composite steel structure, comprising: a transverse steel 2, a vertical steel 1 and a plurality of inclined steels 3. The transverse steel 2 is fixed to the bottom of the vertical steel 1, and the vertical steel 1 is perpendicular to the transverse steel 2, thereby forming a "⊥"-shaped structure. The vertical steel 1 is an H-shaped steel, and the transverse steel 2 is an H-shaped steel, and is connected and fixed by the inclined steel 3. The inclined steels 3 are respectively located on both sides of the vertical steel 1, with one end fixed to the surface of the transverse steel 2 and the other end fixed to the side of the vertical steel 1. The two inclined steels 3 are symmetrically arranged with respect to the vertical steel 1, which play a role of mutual support on the vertical steel 1, thereby increasing the stability of the steel structure.

[0048] From the foregoing, it is readily apparent that the present invention incorporates a "⊥"-shaped composite steel structure within the cement-soil wall 4, with two diagonal steel bars 3 added at the bottom to provide support between the vertical steel 1 and the transverse steel 2. Compared to conventional cement-soil walls 4 with H-shaped steel inserted, this design exhibits superior self-stabilization and shear resistance, effectively preventing damage to the retaining structure caused by kicking, and ensuring the overall stability and safety of the foundation pit.

[0049] Optionally, in this embodiment, the horizontal steel section 2, the vertical steel section 1 and the diagonal steel section 3 are connected by welding so that their connected surfaces are fused together, making the connection more secure. When the steel section structure is processed, manufactured and welded, it must be ensured to be flat and vertical, and no distortion is allowed.

[0050] The construction method of the foundation pit retaining structure of the present invention comprises the following steps:

[0051] S10. Construct the cement-soil mixing wall 4. Before construction, dig a guide trench, use an excavator to excavate the trench, and remove underground obstacles. Excess soil in the trench should be promptly disposed of to ensure normal operation of the equipment. After the trench excavation is completed, construct the cement-soil mixing wall 4 to form a continuous cement-soil body 4.

[0052] S20. Construct high-pressure rotary jet piles 5 of a certain width and depth at the bottom of the cement soil wall 4 to mix the soil. During the construction of the high-pressure rotary jet piles 5, construction parameters such as the grouting pipe rotation speed, grouting pressure, and air pressure should be controlled.

[0053] S30. During transportation and stacking, the composite steel structure must be supported stably and firmly fixed to prevent warping and deformation. When hoisting the composite steel structure, the lifting points should be set reasonably. Before lifting, a central circular hole with a diameter of 100mm should be opened at 150mm from the top of the composite steel structure, and the lifting equipment and fixing hooks should be installed. When the crane lifts the composite steel structure, it should be ensured that the steel structure does not deform during the lifting process. The horizontal error and vertical error of the steel should be adjusted at any time during the insertion of the composite steel structure. The construction of the steel structure inserted into the cement soil wall 4 must be completed within 30 minutes after the pile is formed. After the steel structure is inserted into the high-pressure rotary jet pile 5, it should be immediately rotated 90° in the high-pressure rotary jet pile 5 so that the horizontal steel 2 is perpendicular to the edge of the foundation pit.

[0054] Optionally, in this embodiment, S10 specifically includes the following steps:

[0055] S101. Before construction, determine the construction process of the cement soil wall 4, the mixing sinking and lifting speeds, the cement addition amount and the mix ratio and other related parameters.

[0056] Optionally, in this embodiment, S20 specifically includes the following steps:

[0057] S201. Preset the drilling, rotation and lifting speed, air pressure, shotcrete and other construction parameters of the high-pressure jet pile driver.

[0058] S202. Preset the amount of cement slurry sprayed when the high-pressure jet pile driver rotates and lifts.

[0059] Optionally, in this embodiment, S30 specifically includes the following steps:

[0060] S301. To ensure the verticality of the composite steel structure, a positioning frame can be set up. The positioning frame should be manufactured, placed and fixed according to the site and the size of the steel structure. Displacement is not allowed during the process of inserting the steel structure into the cement soil wall 4 and the high-pressure rotary grouting piles 5. After the crane lifts the composite steel structure, use a total station to adjust its verticality. Then, insert the vertical composite steel structure with the center facing the cement soil wall 4 and the high-pressure rotary grouting piles 5. Slowly insert it into the cement soil wall 4 and the high-pressure rotary grouting piles 5 along the positioning frame. When it is inserted 1 / 3 into the cement soil wall 4, it can be quickly released. The verticality deviation of the composite steel structure is controlled within 1%. If the steel structure cannot sink by its own weight, it can be inserted into place with the help of appropriate external force. If the steel structure is found to be tilted during the insertion process, it should be immediately pulled out to a certain height and then reinserted.

[0061] S302, the combined steel structure inserted into the cement-soil wall 4 and the high-pressure jet grouting pile 5 should be derusted and cleaned to make the surface of the combined steel structure smoother so as to reduce the friction between the combined steel structure and the cement-soil wall 4 and the high-pressure jet grouting pile 5. After the steel structure is derusted and cleaned, a friction-reducing agent should be evenly brushed on the surface of the steel structure, and the thickness of the friction-reducing agent is preferably 2mm. The special friction-reducing agent must be heated to complete melting by an electric heating rod, and the thickness of the friction-reducing agent should be uniform when it is stirred by a stirring rod so as to be applied to the self-stabilizing assembled combined steel structure.

[0062] Optionally, the embodiment further includes:

[0063] S40, after the combined steel structure is inserted into the cement-soil wall 4 and the high-pressure jet grouting pile 5, when the cement-soil wall 4 and the high-pressure jet grouting pile 5 reach the design strength requirement, the foundation pit can be dug after all preparations are completed.

[0064] S50, the underground structure is constructed between the enclosure structures.

[0065] S60, after the underground structure is constructed, there will be gaps between the enclosure structures and the underground structure, and the gaps need to be backfilled in time.

[0066] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be that the first feature directly contacts the second feature, or the first feature indirectly contacts the second feature through an intermediate medium.

[0067] Moreover, the first feature can be above or obliquely above the second feature, or it only means that the first feature is higher than the second feature in horizontal height. The first feature can be below or obliquely below the second feature, or it only means that the first feature is lower than the second feature in horizontal height.

[0068] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A construction method of a self-stabilizing assembled support structure, used in foundation pit support, characterized in that: The self-stabilizing assembled support structure includes: a cement soil wall and a plurality of combined steel sections; A plurality of the combined steel sections are inserted into the cement soil wall; The combined steel includes: horizontal steel, vertical steel, and multiple oblique steels; The transverse section steel is located at the bottom of the vertical section steel, and the vertical section steel is perpendicular to the transverse section steel, and the transverse section steel and the vertical section steel form a "⊥"-shaped structure; One end of the plurality of inclined steels is fixed on the transverse section steel, and the other end is fixed on the vertical section steel, and the inclined steel is used to support the transverse section steel and the vertical section steel; The horizontal steel sections, vertical steel sections and multiple diagonal steel sections constitute a combined steel structure; The method comprises the following steps: S10, constructing a cement soil wall; S20, using high-pressure jet grouting pile construction equipment to drill and spray high-pressure jet grouting piles of a preset width and depth at the bottom of the cement soil wall; S30. Before the cement-soil mixture hardens, multiple composite steel structures are inserted into the cement-soil wall at preset distances and rotated 90 degrees.

2. The construction method of the self-stabilizing assembled support structure according to claim 1, characterized in that: The vertical steel is H-shaped steel, and the horizontal steel is H-shaped steel.

3. The construction method of the self-stabilizing assembled support structure according to claim 1, characterized in that: The transverse steel sections, the vertical steel sections and the oblique steel sections are fixed by welding.

4. The construction method of the self-stabilizing assembled support structure according to claim 1, characterized in that: The S10 specifically includes the following steps: S101. Before construction, determine the cement-soil mixing pile / wall construction process, mixing sinking and lifting speed, cement addition amount and mix ratio related parameters.

5. The construction method of the self-stabilizing assembled support structure according to claim 1, characterized in that: The S20 specifically includes the following steps: S201. Preset the drilling, rotation and lifting speed, air pressure, and grouting construction parameters of the high-pressure jet pile driver; S202. Preset the amount of cement slurry sprayed when the high-pressure jet pile driver rotates and lifts.

6. The construction method of the self-stabilizing assembled support structure according to claim 1, characterized in that: The S30 specifically includes the following steps: S301. Apply drag reducing agent on the surface of the composite steel structure; S302. Adjust the verticality of the steel structure during the process of inserting the combined steel structure.

7. The construction method of the self-stabilizing assembled support structure according to claim 6, characterized in that: The following steps are also included: S40, digging foundation pit; S50. Construction of underground structures between foundation pit retaining structures; S60. Backfill earth between the foundation pit retaining structure and the underground structure.

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