Composite diaphragm wall foundation and construction method thereof

Abstract

The application discloses a composite diaphragm wall foundation, which comprises cement mixing piles and a diaphragm wall, the cement mixing piles are arranged in two rings in a ring shape, and the diaphragm wall is arranged between the two rings of cement mixing piles; a partition wall is arranged in a foundation pit formed by the inner ring of cement mixing piles, the partition wall comprises a central circular partition wall arranged in the middle, a plurality of vertical partition walls are arranged outside the central circular partition wall, and the vertical partition walls are connected to the inner side of the inner ring of cement mixing piles.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, in particular to a composite ground-connected wall foundation and a construction method thereof. Background Art

[0002] Currently, most large-scale bridge foundations in China are based on pile groups, with some railway bridges employing caisson foundations. However, when the geological conditions of the main piers are poor, especially when a tectonic fracture zone exists below, traditional large-diameter pile foundations are unsuitable. This is because, in soft strata, the piles are designed to be long, and the tectonic fracture zone lies within the designed length of the piles, resulting in uneven stress on the piles. Furthermore, the piles are too long to penetrate deep below the fracture zone. Furthermore, in complex geological conditions such as those adjacent to important structures like levees, where groundwater resources are abundant and the ground is highly permeable, caisson foundations pose a significant safety hazard to surrounding structures due to the need to excavate soil during construction. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a composite ground-connected wall foundation and a construction method thereof, wherein the structure is shallower than the traditional pile foundation and can ensure that the construction period has little impact on the surrounding environment.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is: a composite ground-connected wall foundation, comprising cement mixing piles and a ground-connected wall, wherein the cement mixing piles are arranged in two circles in a ring shape, and the ground-connected wall is arranged between the two circles of cement mixing piles;

[0005] A partition wall is set in the foundation pit formed by the cement mixing piles located in the inner circle. The partition wall includes a central circle partition wall located in the middle. A plurality of vertical partition walls are set on the outside of the central circle partition wall. The vertical partition walls are connected to the inner side of the inner circle cement mixing piles.

[0006] In a preferred solution, the bottom of the ground-connected wall is arranged close to the bottom of the cement mixing pile, and grouting is performed at the bottom of the ground-connected wall to form a water-stopping slurry.

[0007] In a preferred solution, the foundation pit is excavated to the height of the water-stopping slurry, a bottom plate is cast at the bottom of the foundation pit, and a connection is formed between the bottom plate and the water-stopping slurry.

[0008] In a preferred solution, a cap beam is provided on the top of the ground-connected wall, and the cap beam connects the ground-connected wall cast in sections to form a whole.

[0009] The construction method of the composite ground-connected wall foundation comprises the following steps:

[0010] 1) Construct two circles of cement mixing piles on the outer layer of the construction area;

[0011] 2) Construct concrete guide walls along two circles of cement mixing piles;

[0012] 3) Excavate a mud mixing tank and a slurry storage tank on site and set up a mud circulation system;

[0013] 4) The trench section is excavated between two circles of cement mixing piles, and the steel cage is lowered and concrete is poured to form the wall;

[0014] 5) Use the grouting pipe to inject high-pressure slurry into the sediment layer at the bottom of the ground-connected wall, and form a water-stopping slurry at the bottom of the ground-connected wall that spreads toward the soil;

[0015] 6) After removing the concrete guide wall, the cap beam is constructed to connect the concrete guide wall to form a whole;

[0016] 7) Carry out excavation of the middle foundation pit;

[0017] 8) After excavation to the design elevation, tie the bottom plate reinforcement and cast the bottom plate in layers;

[0018] 9) Carry out partition wall construction to form central circle partition wall and vertical partition wall;

[0019] 10) Construct the concrete top slab on the top of the foundation pit.

[0020] In a preferred solution, in step 4), the ground-anchored wall reinforcement cage is positioned by a concrete guide wall after being suspended.

[0021] In a preferred solution, in step 7), after the foundation pit is excavated to a level close to the bottom elevation of the cement mixing pile (1), manual excavation is used to reach the designed elevation and expose the water-stop slurry.

[0022] In a preferred solution, in step 8), the base plate is cast and formed into a whole with the water-stop slurry.

[0023] In a preferred embodiment, the step 9) specifically comprises the following steps:

[0024] 9.1) Install inner and outer layers of central formwork at the center of the base plate and cast the central circle partition wall;

[0025] 9.2) After the central circle partition wall is formed, the outer circle central formwork is removed and the vertical partition wall formwork is installed between the central circle partition wall and the inner circle cement mixing piles;

[0026] 9.3) Pour concrete into the vertical partition wall formwork to form the vertical partition wall. During this process, set up the upper center formwork above the vertical partition wall formwork and pour the upper center circle partition wall.

[0027] 9.4) Repeat the above steps to complete the layered casting and molding construction of the partition wall.

[0028] In the preferred solution, in the central formwork, the formwork located in the inner circle is integral, and its upper end is flush with the top surface of the foundation pit; the formwork located in the outer circle is assembled, and the outer circle formwork is erected layer by layer to achieve the purpose of segmented construction of the central circle partition wall.

[0029] The present invention provides a foundation support and abutment formwork structure for a main pier adjacent to the Yangtze River levee. By adopting the above structure and method, it has the following beneficial effects:

[0030] (1) It has the excellent construction characteristics of a general underground continuous wall foundation. At the same time, the structural stress is clear, the depth of burial is relatively small, the construction risk is small, and it can adapt to complex stratum environments. It is especially suitable for strata with strong permeability, such as the lower fracture zone, the embankment, and the stratum;

[0031] (2) Compared with the large-diameter pile foundation, the composite underground continuous wall foundation provided by the present invention has good integrity. The pile foundation is an independent component that bears force alone under the pedestal, while the composite underground continuous wall foundation provided by the present invention is a whole, and the "pile group effect" of the foundation is greatly reduced;

[0032] (3) Compared with the caisson foundation, the composite ground-anchored wall foundation provided by the present invention uses the outer ground-anchored wall as the supporting structure, forming an "expanded foundation" with a supporting structure as a whole. When the foundation pit is excavated and soil is taken, the impact on the levee is small, and at the same time, groundwater can be prevented from seeping into the foundation pit and affecting the construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below with reference to the accompanying drawings and examples:

[0034] Figure 1 It is a schematic diagram of the construction of cement mixing piles according to the present invention.

[0035] Figure 2 Schematic diagram of the construction of the ground-connected wall according to the present invention.

[0036] Figure 3 It is a schematic diagram of foundation pit excavation and formwork erection according to the present invention.

[0037] Figure 4 This is a schematic diagram of the construction of the lower vertical partition wall and the middle center circle partition wall according to the present invention.

[0038] Figure 5 This is a schematic diagram of the construction of the middle vertical partition wall and the upper center circle partition wall according to the present invention.

[0039] Figure 6 It is a schematic diagram of the top structure of the present invention.

[0040] In the figure: cement mixing pile 1, concrete guide wall 2, ground-connected wall 3, grouting pipe 4, water-stop slurry 5, cap beam 6, bottom plate 7, center formwork 8, center circle partition wall 9, vertical partition wall formwork 10, vertical partition wall 11. DETAILED DESCRIPTION

[0041] Example 1:

[0042] like Figure 5 、 6 In the embodiment, a composite ground-connected wall foundation comprises cement mixing piles 1 and ground-connected walls 3, wherein the cement mixing piles 1 are arranged in two circles in a ring shape, and the ground-connected walls 3 are arranged between the two circles of cement mixing piles 1;

[0043] A partition wall is set in the foundation pit formed by the cement mixing piles 1 located in the inner circle, and the partition wall includes a central circular partition wall 9 located in the middle. A plurality of vertical partition walls 11 are set on the outside of the central circular partition wall 9, and the vertical partition walls 11 are connected to the inner side of the inner circle cement mixing piles 1.

[0044] In a preferred solution, the bottom of the ground-connected wall 3 is arranged close to the bottom of the cement mixing pile 1, and grouting is performed at the bottom of the ground-connected wall 3 to form a water-stopping slurry 5.

[0045] In a preferred solution, the foundation pit is excavated to the height of the water-stopping slurry 5 , and a bottom plate 7 is cast at the bottom of the foundation pit, forming a connection between the bottom plate 7 and the water-stopping slurry 5 .

[0046] In a preferred solution, a cap beam 6 is provided on the top of the ground-connected wall 3, and the cap beam 6 connects the ground-connected wall 3 cast in sections to form a whole.

[0047] Example 2:

[0048] like Figure 1-5 In the embodiment 1, the construction method of the composite ground-connected wall foundation includes the following steps:

[0049] 1) Construct two circles of cement mixing piles 1 on the outer layer of the construction area to enhance the stability of the trench wall;

[0050] 2) Concrete guide walls 2 are constructed along two circles of cement mixing piles 1. These serve as surface support and retain the soil when the ground connection wall 3 is formed. This also improves the accuracy and verticality of the trenching process.

[0051] 3) Excavate a mud mixing tank and a slurry storage tank on site and set up a mud circulation system;

[0052] 4) The trench section is excavated between two circles of cement mixing piles 1, and the steel cage is lowered and concrete is poured to form the wall;

[0053] 5) Use the grouting pipe 4 to perform high-pressure grouting on the sediment layer at the bottom of the ground-connected wall 3, and form a water-stopping grout 5 at the bottom of the ground-connected wall 3 that spreads toward the soil;

[0054] 6) After removing the concrete guide wall 2, the cap beam 6 is constructed to connect the concrete guide wall 2 to form a whole and prevent the top edge of the ground-connected wall 3 from collapsing;

[0055] 7) Carry out excavation of the middle foundation pit;

[0056] 8) After excavation to the design elevation, tie the bottom plate reinforcement and cast the bottom plate 7 in layers;

[0057] 9) Carry out partition wall construction to form a central circle partition wall 9 and a vertical partition wall 11;

[0058] 10) Construct the concrete top slab on the top of the foundation pit.

[0059] In a preferred solution, in step 4), the reinforcement cage of the ground-connected wall 3 is positioned by the concrete guide wall 2 after being suspended.

[0060] In a preferred solution, in step 7), the foundation pit is excavated mechanically to a height close to the bottom elevation of the cement mixing pile 1 , and then manually excavated to the designed elevation to expose the water-stop slurry 5 .

[0061] In a preferred solution, in step 8), the base plate 7 is cast and formed into a whole with the water-stop slurry 5 .

[0062] Example 3:

[0063] like Figure 3-5 In the embodiment 2, the partition wall construction method specifically includes:

[0064] 9.1) Install inner and outer center formwork 8 at the center of the base plate 7 and cast the center circle partition wall 9;

[0065] 9.2) After the center circle partition wall 9 is formed, the outer circle center formwork 8 is removed and the vertical partition wall formwork 10 is installed between the center circle partition wall 9 and the inner circle cement mixing pile 1;

[0066] 9.3) Concrete is poured into the vertical partition wall formwork 10 to form the vertical partition wall 11. During this process, the upper center formwork 8 is further set above the vertical partition wall formwork 10 and the upper center circle partition wall 9 is poured;

[0067] 9.4) Repeat the above steps to complete the layered casting and molding construction of the partition wall.

[0068] In the preferred solution, in the central formwork 8, the formwork located in the inner circle is integral, and its upper end is flush with the top surface of the foundation pit, and the formwork located in the outer circle is assembled, and the outer circle formwork is erected layer by layer to achieve the purpose of segmented construction of the central circle partition wall 9.

[0069] When the above-mentioned integral inner ring formwork is used, the inner ring formwork is installed in place at one time, and the outer ring formwork can be gradually lifted and installed during the subsequent layered pouring process.

[0070] After completing the overall construction of the above foundation, the foundation and subsequent tower columns can be constructed on the top concrete slab.

[0071] The composite underground continuous wall foundation provided by the present invention adopts a rigid closed wall body, which makes the force on the wall body more clear, is more conducive to construction under unfavorable geological conditions, and reduces the impact on structures such as embankments.

Claims

1. A construction method for a composite ground-connected wall foundation, characterized by: The composite ground-connected wall foundation comprises cement mixing piles (1) and ground-connected walls (3), wherein the cement mixing piles (1) are arranged in two circles in a ring shape, and the ground-connected walls (3) are arranged between the two circles of cement mixing piles (1); A partition wall is provided in the foundation pit formed by the cement mixing piles (1) in the inner circle, the partition wall including a central circular partition wall (9) in the middle, a plurality of vertical partition walls (11) are provided on the outer side of the central circular partition wall (9), and the vertical partition walls (11) are connected to the inner side of the inner circle cement mixing piles (1); The above-mentioned construction method of a composite ground-connected wall foundation comprises the following steps: 1) Construct two circles of cement mixing piles (1) on the outer layer of the construction area; 2) Constructing concrete guide walls (2) along two circles of cement mixing piles (1); 3) Excavate a mud mixing tank and a slurry storage tank on site and set up a mud circulation system; 4) The trench section is excavated between two circles of cement mixing piles (1), and the steel cage is lowered and concrete is poured to form the wall; 5) Using a grouting pipe (4), high-pressure grouting is performed on the sediment layer at the bottom of the ground-connected wall (3), and a water-stopping grout (5) is formed at the bottom of the ground-connected wall (3) that spreads toward the soil. 6) After removing the concrete guide wall (2), the cap beam (6) is constructed to connect the concrete guide wall (2) to form a whole; 7) Carry out excavation of the middle foundation pit; 8) After excavation to the design elevation, tie the bottom plate reinforcement and cast the bottom plate in layers (7); 9) Carry out partition wall construction to form a central circle partition wall (9) and a vertical partition wall (11); 10) Construct the concrete top slab on the top of the foundation pit; The step 9) specifically includes the following steps: 9.1) Install the inner and outer layers of the center formwork (8) at the center of the base plate (7), and perform the pouring and molding construction of the center circle partition wall (9); 9.2) After the center circle partition wall (9) is formed, the center formwork (8) of the outer circle is removed and the vertical partition wall formwork (10) is installed between the center circle partition wall (9) and the inner circle cement mixing pile (1); 9.3) Concrete is poured into the vertical partition wall formwork (10) to form the vertical partition wall (11). During this process, an upper center formwork (8) is further set up above the vertical partition wall formwork (10) and the upper center circle partition wall (9) is poured; 9.4) Repeat the above steps to complete the layered casting and molding construction of the partition wall.

2. The construction method of a composite ground-connected wall foundation according to claim 1, characterized in that: The bottom of the ground-connected wall (3) is arranged close to the bottom of the cement mixing pile (1), and grouting is performed at the bottom of the ground-connected wall (3) to form a water-stopping grouting body (5).

3. The construction method of a composite ground-connected wall foundation according to claim 2, characterized in that: The foundation pit is excavated to the height of the water-stopping slurry (5), and a bottom plate (7) is poured at the bottom of the foundation pit, forming a connection between the bottom plate (7) and the water-stopping slurry (5).

4. The construction method of a composite ground-connected wall foundation according to claim 1, characterized in that: A cap beam (6) is provided on the top of the ground-connected wall (3), and the cap beam (6) connects the ground-connected wall (3) cast in sections to form a whole.

5. The construction method of a composite ground-connected wall foundation according to claim 1, characterized in that: In the step 4), the steel cage of the ground-connected wall (3) is lowered and positioned by the concrete guide wall (2).

6. The construction method of a composite ground-connected wall foundation according to claim 1, characterized in that: In the step 7), the foundation pit is excavated by mechanical excavation to a height close to the bottom elevation of the cement mixing pile (1), and then manually excavated to the designed elevation to expose the water-stop slurry (5).

7. The construction method of a composite ground-connected wall foundation according to claim 1, characterized in that: In the step 8), the base plate (7) is poured and formed into a whole with the water-stop slurry (5).

8. The construction method of a composite ground-connected wall foundation according to claim 1, characterized in that: In the central template (8), the template located in the inner circle is an integral type, and its upper end is flush with the top surface of the foundation pit. The template located in the outer circle is an assembled type, and the outer circle templates are erected layer by layer to achieve the purpose of segmented construction of the central circle partition wall (9).

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