A construction method for isolation piles adjacent to a building
By using a combination of H-beams and MJS piles in deep foundation pit construction, the problems of high manpower and material consumption and serious structural impact during the construction of adjacent buildings were solved, thereby improving construction stability and safety and reducing construction interference and noise to the surrounding environment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI TUNNEL ENG CO LTD
- Filing Date
- 2023-11-16
- Publication Date
- 2026-05-29
AI Technical Summary
In deep foundation pit construction, when the pit is close to a building, conventional support measures consume a lot of manpower and resources and have a serious impact on the building structure, making it difficult to guarantee construction stability and safety.
The construction method adopts a combination of H-beams and MJS piles. By setting up a retaining isolation zone between the foundation pit and the building structure, the first and second rows of MJS piles are jet-grouted to enhance the soil strength and reduce water permeability. High-frequency non-resonant hammers are used to drive H-beams to reduce disturbance.
It effectively reduced the impact of foundation pit construction on the building structure, improved construction stability and safety, reduced construction interference and noise on the surrounding environment, and enhanced the continuity of soil support and waterproof performance.
Smart Images
Figure CN117431964B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of building structural engineering, and specifically to a construction method for isolation piles used near adjacent buildings. Background Technology
[0002] In recent years, my country's urban construction has developed rapidly, with an increasing number of high-rise buildings and deep foundation pit projects. The scale, depth, and construction difficulty of these deep foundation pits have also increased year by year. Especially in old urban areas and important structural buildings, where deep foundation pits are adjacent to existing or ancient building structures, the excavation of these pits can have a very serious impact on the old building structures, such as subsidence, cracking, or even collapse.
[0003] To ensure the stability and safety of the building structure during subsequent construction, a series of measures need to be taken to reinforce the building structure. The conventional approach is to install supports on the outside of the building structure to enhance its stability and seismic resistance. However, this approach consumes a great deal of manpower and resources. Alternatively, the building structure can be moved without alteration. This method causes less damage to the building structure, but it requires even more manpower and resources. Summary of the Invention
[0004] The purpose of this invention is to overcome the deficiencies of the prior art and provide a construction method for isolation piles used near buildings. The H-beams provide support for the edge of the foundation pit. By jet grouting a first row of MJS method piles and a second row of MJS method piles between the foundation pit and the building structure, the strength of the soil between the foundation pit and the building structure is strengthened, reducing the impact on the building structure during foundation pit construction. The first row of MJS method piles and the second row of MJS method piles partially overlap to increase the permeability between the foundation pit and the building structure.
[0005] The technical solution to achieve the above objective is a construction method for isolation piles used near buildings, which are set between the foundation pit and the building structure, including the following steps: constructing a retaining isolation area between the foundation pit and the building structure, wherein the retaining isolation area is set along the extension direction of the foundation pit;
[0006] Several H-beams are installed at intervals in the pre-drilled holes on the side of the enclosure and isolation area closest to the foundation pit;
[0007] A number of first-row MJS oscillating spray holes are drilled at intervals on the side of the enclosure isolation area and close to the building structure. The first row of MJS oscillating spray holes is located between two adjacent H-beams, and the depth of the first row of MJS oscillating spray holes is the same as the drilling depth of the H-beams.
[0008] Grouting is performed in the first row of MJS swing jet holes and 180 degrees is rotated to form the first row of MJS method piles. The arc-shaped section of the first row of MJS method piles is set away from the building structure, and two adjacent first row of MJS method piles partially overlap.
[0009] A second row of MJS spray holes is drilled on the side of the enclosure isolation area close to the foundation pit and opposite to the first spray hole. The depth of the second row of MJS spray holes is the same as the depth of the H-beam.
[0010] Grouting is performed at the second row of MJS swivel jet holes and a 180-degree rotary jet is used to form the second row of MJS method piles. The arc-shaped section of the second row of MJS method piles is set away from the foundation pit. There is partial overlap between adjacent second rows of MJS method piles, and the arc-shaped sections of the first row of MJS method piles and the second row of MJS method piles are tangent.
[0011] Furthermore, during the installation of the H-beam, a positioning element is provided. The positioning element provides a positioning space for inserting the H-beam, which is placed on the top of the soil. The H-beam is inserted into the positioning space so that the positioning element positions the H-beam.
[0012] Furthermore, the distance between the first row of MJS method piles and the building structure is adapted to the distance between the second row of MJS method piles and the foundation pit.
[0013] Furthermore, the distance between the first row of MJS swivel jet holes and the second row of MJS swivel jet holes is matched with the sum of the radii between the first row of MJS method piles and the second row of MJS method piles.
[0014] Furthermore, the radius of the first pile and the radius of the second pile are equal.
[0015] Furthermore, the foundation pit is also provided with a corner, and the protective isolation area is provided with a corner guard on the side of the foundation pit close to the corner after the jet grouting first method pile;
[0016] Furthermore, the H-beam is installed in the soil by high-frequency non-resonance hammering through pre-drilled holes.
[0017] Furthermore, the first row of MJS method piles and the second row of MJS method piles are installed using the MJS method.
[0018] Compared with the prior art, the present invention has the following advantages:
[0019] The H-beams are driven into the building edge by pre-drilling holes and then driven with a high-frequency non-resonant hammer, allowing them to be installed with minimal disturbance to the surrounding soil. The H-beams provide isolation for the edge of the foundation pit. By jet grouting the first row of MJS method piles and the second row of MJS method piles between the foundation pit and the building structure, the strength of the soil between the foundation pit and the building structure is enhanced, reducing the impact on the building structure during foundation pit construction. Attached Figure Description
[0020] Figure 1 This is an overall structural diagram of a construction method for isolation piles used near buildings according to the present invention.
[0021] Figure 2 This is a diagram illustrating the effect of using a positioning component in a construction method for a retaining isolation pile installed close to the edge of a foundation pit, as described in this invention.
[0022] Legend: 1. Foundation pit; 11. H-beam; 12. Second row of MJS method piles; 13. Positioning component; 2. Building structure; 21. First row of MJS method piles. Detailed Implementation
[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0024] See Figure 1 A construction method for isolation piles used near buildings, located between a foundation pit 1 and a building structure 2, includes the following steps: constructing a retaining isolation zone between the foundation pit and the building structure, the retaining isolation zone being set along the extension direction of the foundation pit; driving a plurality of H-beams at intervals through pilot holes within the retaining isolation zone and on the side near the foundation pit; driving a plurality of first-row MJS swivel jet holes at intervals through pilot holes within the retaining isolation zone and on the side near the building structure, the first-row MJS swivel jet holes being located between two adjacent H-beams, the depth of the first-row MJS swivel jet holes being consistent with the driving depth of the H-beams 11; grouting and rotary jetting 180 degrees through the first-row MJS swivel jet holes to form... The first row of MJS method piles 21 has an arc-shaped section that is away from the building structure, and two adjacent first row MJS method piles 21 partially overlap. A second row of MJS swivel nozzles is drilled in the retaining isolation area near the predicted position of the foundation pit and at a position opposite to the first row of MJS swivel nozzles. The depth of the second row of MJS swivel nozzles is the same as the depth of the H-beam 11. Grouting is performed in the second row of MJS swivel nozzles and a 180-degree rotary jet grouting is used to form a second row of MJS method piles 12. The arc-shaped section of the second row of MJS method piles 12 is away from the foundation pit, and the arc-shaped sections of the first row of MJS method piles 21 and the second row of MJS method piles 12 are tangent.
[0025] In this invention, a preferred embodiment is as follows: Holes are drilled in the soil at the edge of the foundation pit 1, and several H-beams 11 are installed. The H-beams 11 are vertically driven into the soil to increase soil strength and prevent soil collapse or subsidence. On the side of the building structure 2 closest to the foundation pit 1, several first-row MJS swivel jet grouting holes are drilled using equipment, and grout is injected into these holes. The grouting material is generally cement grout or polymer grout. To prevent potential safety risks to the building structure 2 due to the grouting pressure, the cement grout is not pressurized towards the building structure 2, resulting in a swivel jetting angle of 180 degrees to form a semi-circular structure. During grouting, the grouting equipment is gradually raised to avoid uneven distribution of the grout within the soil. After grouting, several first-row MJS method piles 21 are formed. The piles 21 overlap partially to form a waterproof section. A second row of MJS swivel jet holes is drilled between the two H-beams 11, and grout is injected into these holes. To prevent the cement grout from damaging the sidewalls of the pit 1 due to grouting pressure, the grout is not injected under pressure towards the pit 1, resulting in a swivel jet angle of 180 degrees to form a semi-circular structure. After grouting, several second-row MJS piles 12 are formed, with partial overlap between them to form a water-stop section, effectively preventing groundwater infiltration and leakage. The second-row MJS piles 12 also partially overlap with the first-row MJS piles 21 to increase the continuity of the support and reduce gaps between supports, effectively preventing soil subsidence and sliding, making the entire support structure more stable and reliable.
[0026] Furthermore, the H-beam 11 is made of HN700*300 steel, which has a simple structure and is easy to obtain.
[0027] Furthermore, during the installation of the H-beam 11, a positioning element 13 is provided. The positioning element 13 is installed on top of the soil to position the H-beam 11. The positioning element 13 includes a side plate and two clamping plates installed on the side plate. The distance between the two clamping plates is adapted to the distance between the two opposing structural plates of the H-beam. The positioning element 13 is fixed at the installation position of the H-beam 11. During the installation of the H-beam, the H-beam is placed on the side wall of the clamping plate. Preferably, the two clamping plates are located between the two H-beams. Then, the H-beam 11 is installed in the soil. To ensure positioning accuracy, two positioning elements 13 are provided, with the two positioning elements 13 located at opposite ends of the H-beam.
[0028] Furthermore, the distance between the first row of MJS method piles and the building structure is adapted to the distance between the second row of MJS method piles and the foundation pit.
[0029] Furthermore, the distance between the first row of MJS swivel jet holes and the second row of MJS swivel jet holes is matched with the sum of the radii between the first row of MJS method piles and the second row of MJS method piles.
[0030] Furthermore, the radius of the first row of MJS method piles is equal to the radius of the second row of MJS method piles.
[0031] Furthermore, the foundation pit is also provided with a corner, and the protective isolation area is provided with a corner guard on the side of the foundation pit close to the corner after the first row of MJS method piles by jet grouting.
[0032] Furthermore, the H-beam 11 is driven into the soil using a high-frequency non-resonant hammer. The high-frequency non-resonant hammer has a high impact frequency, enabling the H-beam 11 to be driven into the soil quickly, and the vibration amplitude generated during impact is small, reducing the impact on surrounding structures. This avoids damage to the foundation pit 1 structure and building structure 2 due to excessive impact during construction. Preferably, an ICE high-frequency non-resonant hammer is used to drive the H-beam 11.
[0033] Furthermore, the first row of MJS method piles 21 and the second row of MJS method piles 12 are driven using the MJS method. The MJS method reduces construction time and minimizes interference and impact on the surrounding environment, while also offering fast construction speed and minimizing vibration and noise.
[0034] The following describes the process of using a construction method for isolation piles used near buildings according to the present invention.
[0035] Several H-beams 11 are driven vertically into the soil at the edge of the foundation pit 1 to provide vertical support and prevent soil collapse or subsidence. Several first-row MJS jet grouting holes are drilled into the soil on the side of the building structure 2 closest to the foundation pit 1 using an MJS device, and grout is injected into these holes. The grouting material is typically cement grout or polymer grout. To prevent potential safety risks to the building structure 2 due to the grouting pressure, the cement grout is not injected towards the building structure 2 under pressure, resulting in a 180-degree jet grouting angle to form a semi-circular structure. During grouting, the grouting equipment is gradually raised to avoid uneven distribution of grout within the soil. After grouting, several first-row MJS method piles 21 are formed, with spacing between them. Partial overlap is formed to create a seepage-proof section. A second row of MJS swivel jet holes is drilled between the two H-beams 11, and grout is injected into these holes. To prevent damage to the sidewalls of the pit 1 due to grouting pressure, the grout is not injected under pressure towards the pit 1, resulting in a swivel jet angle of 180 degrees to form a semi-circular structure. After grouting, several second-row MJS piles 12 are formed, with partial overlap between them to create a water-stop section. This effectively prevents groundwater infiltration and leakage. Furthermore, there is partial overlap between the second-row MJS piles 12 and the first-row MJS piles 21, increasing the continuity of the support and reducing gaps between supports. This effectively prevents soil subsidence and sliding, making the entire support structure more stable and reliable.
[0036] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.
Claims
1. A construction method for isolation piles used near buildings, wherein the piles are installed between the foundation pit and the building structure, characterized in that, The steps include: constructing an enclosure and isolation zone between the foundation pit and the building structure, wherein the enclosure and isolation zone is set along the extension direction of the foundation pit; Several H-beams are installed at intervals in the enclosure and isolation area, on the side closest to the foundation pit; After drilling several H-beams at intervals on the side of the enclosure and isolation area close to the building structure, several first row of swing spray holes are drilled at intervals. The first row of swing spray holes is located between two adjacent H-beams, and the depth of the first row of swing spray holes is the same as the drilling depth of the H-beams. Grouting is performed in the first row of swing jet holes and 180 degrees of rotary jetting to form the first row of MJS method piles. The arc-shaped section of the first row of MJS method piles is set away from the building structure, and two adjacent first row of MJS method piles partially overlap. A second row of swing spray holes is drilled on the side of the enclosure isolation area close to the foundation pit and opposite to the first row of swing spray holes. The depth of the second row of swing spray holes is the same as the depth of the H-beam. Grouting is performed in the second row of swing jet holes and 180 degrees of rotary jetting to form the second row of MJS method piles. The arc-shaped section of the second row of MJS method piles is set away from the foundation pit. There is partial overlap between adjacent second rows of MJS method piles, and the arc-shaped sections of the first row of MJS method piles and the second row of MJS method piles are tangent. The distance between the first row of swivel jet holes and the second row of swivel jet holes is adapted to the sum of the radii between the first row of MJS method piles and the second row of MJS method piles; The radius of the first row of MJS method piles is equal to the radius of the second row of MJS method piles.
2. The construction method for isolation piles used near buildings according to claim 1, characterized in that: When installing the H-beam, a positioning element is provided. The positioning element provides a positioning space for inserting the H-beam. The positioning element is set on the top of the soil. The H-beam is inserted into the positioning space so that the positioning element positions the H-beam.
3. The construction method for isolation piles used near buildings according to claim 1, characterized in that: The distance between the first row of MJS method piles and the building structure is matched with the distance between the second row of MJS method piles and the foundation pit.
4. The construction method for isolation piles used near buildings according to claim 1, characterized in that: The foundation pit is also provided with a corner. After the first row of MJS method piles are jet-grouted, the side of the retaining isolation area closest to the foundation pit is provided with a corner guard corresponding to the corner.
5. A construction method for isolation piles used near buildings according to claim 1, characterized in that: The H-beam is installed in the soil by means of a pre-drilled hole and then hammered in with a high-frequency non-resonant hammer.
6. A construction method for isolation piles used near buildings according to claim 1, characterized in that: The first row of MJS method piles and the second row of MJS method piles were installed using the MJS method.