A pile foundation arrangement method for densely packed buildings on large landslide deposits

Abstract

This invention discloses a method for arranging dense building pile foundations on large-scale landslide deposits. The method includes geological surveys; stability analysis of the landslide deposit to delineate hazardous areas; arranging building pile foundations in each hazardous area of ​​the deposit using long and short piles; and reviewing the stability of the deposit, the bearing capacity of the pile foundations, and settlement. This method utilizes a combination of long and short piles, arranged in zones. Long piles are used to resist landslide thrust and control building settlement, while short piles ensure the bearing capacity of the pile foundation. The long and short piles complement and synergize with each other, significantly reducing project costs while ensuring the stability of the deposit and the bearing capacity of the pile foundation.

Description

Technical Field

[0001] The invention relates to the fields of foundation engineering and landslide prevention and control, and mainly relates to a pile foundation arrangement method for densely packed building groups on a large landslide accumulation body. Background Art

[0002] The mountainous and canyon areas in southwest my country have high and steep terrain, complex geological environment, and frequent geological disasters such as landslides. However, with the rapid development of the economy and the gradual reduction of construction land, many buildings will be built on relatively flat landslide deposits. Therefore, there are many technical bottlenecks in the site selection of dense building complexes and landslide prevention and control.

[0003] Relatively flat landslide accumulation areas often have relatively good water sources, land and transportation conditions, but due to their poor anti-disturbance and easy slipperiness, the construction of dense housing complexes faces complex construction site safety control problems.

[0004] At present, the construction of dense building complexes on large landslide deposits mostly uses a large number of anti-slip and load-bearing integrated deep pile foundations. The building pile foundations are all embedded in stable bedrock. The redundant anti-slip design greatly increases the construction cost and difficulty, and the construction period also becomes longer. Therefore, it is of great significance to propose a new method for arranging dense building pile foundations on large landslide deposits. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the invention provides a method for arranging pile foundations of densely packed buildings on large landslide deposits, which solves the design problem of densely packed building pile foundations on large landslide deposits in the existing technology.

[0006] According to an embodiment of the invention, a method for arranging pile foundations of densely packed buildings on a large landslide accumulation body comprises the following steps:

[0007] S1. Conduct geological survey of the landslide deposits where the construction site is located and collect and calculate relevant parameters;

[0008] S2. Conduct stability analysis on the landslide accumulation, calculate the sliding force of the landslide and divide the dangerous area;

[0009] S3. Under each building in the danger zone, arrange different rows of long piles in different positions according to the force of the landslide, and arrange the remaining rows of piles with long piles and short piles alternately;

[0010] S4, calculate whether the stability coefficient of the pile body after reinforcement in step S2 and the pile foundation bearing capacity and settlement meet the design requirements. If not, increase the pile diameter and / or pile length of the long pile and the short pile or increase the number of rows of long piles;

[0011] S5. Repeat step S3 until the stability coefficient of the landslide accumulation body, the pile foundation bearing capacity, and the settlement meet the design requirements.

[0012] Furthermore, in step S1, a geological survey is conducted to collect the type, scale, thickness of the accumulation layer, type of sliding surface, spatial position of the sliding surface, main axis of sliding and physical and mechanical parameters of the rock and soil within the accumulation body; and indoor physical and mechanical performance tests are conducted on the rock and soil layer samples to calculate the sliding force and preliminarily determine the pile length, pile diameter and reinforcement ratio of the long pile and short pile.

[0013] Furthermore, in step S2, a stability analysis is performed on the accumulation body, the dangerous areas of the accumulation body are divided and the failure modes thereof are identified, and the accumulation body is divided into a high-danger area, a medium-danger area and a low-danger area.

[0014] Furthermore, in step S3, the long piles pass through the sliding surface of the accumulation body and are embedded in the stable bedrock, and the embedding depth is not less than 2m.

[0015] Furthermore, in step S3, the bottom of the short pile is above the sliding surface of the accumulation body and is not embedded in the stable bedrock.

[0016] Furthermore, the length of the short pile is 1 / 2 to 4 / 5 of the length of the long pile.

[0017] Furthermore, the long piles and the short piles are both reinforced concrete piles with circular cross-sections.

[0018] Furthermore, in step S3, long piles and short piles are used to arrange building pile foundations in different zones under buildings in different danger levels of the accumulation body; under buildings in low-risk zones, long piles are continuously arranged in at least one row near the front edge of the landslide, and in several rows near the rear edge of the landslide, long piles and short piles are arranged at intervals; under buildings in medium-risk zones, long piles are continuously arranged in at least one row near the rear edge of the landslide, and in several rows near the front edge of the landslide, long piles and short piles are arranged at intervals; under buildings in high-risk zones, long piles are continuously arranged in at least two rows near the rear edge of the landslide, and in several rows near the front edge of the landslide, long piles and short piles are arranged at intervals.

[0019] Furthermore, the distance between the long piles and the adjacent short piles or long piles in the same row is 2 to 4 times the diameter of the short piles.

[0020] Furthermore, the distance between two adjacent rows of piles under the building is 2 to 5 times the diameter of the short piles.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention divides the dangerousness of the accumulation body into different zones based on stability analysis, and adopts different long and short pile combination layout schemes under the buildings in different dangerous areas. The long piles are embedded in the stable bedrock, which can effectively resist the thrust of the landslide and improve the stability of the landslide accumulation body. At the same time, it can control the settlement of the building. The short piles can ensure the bearing capacity of the pile foundation. The advantages of long piles and short piles complement each other and work together to form a combined advantage, which can fully meet the stability requirements of the landslide accumulation body and the pile foundation bearing capacity and settlement requirements of the building.

[0023] (2) The present invention adopts a scheme of combining long and short piles and zoning piles, thereby avoiding the waste caused by the large-scale use of anti-slip and load-bearing integrated deep piles in existing conservative designs, greatly reducing the construction difficulty, thereby shortening the construction period and reducing the project cost. The proposed design method is simple to operate and is conducive to promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the pile foundation arrangement structure of a densely packed building complex on a large landslide accumulation body according to an embodiment of the present invention;

[0025] Figure 2 This is a plan view of the pile foundation under a building in a low-risk area according to an embodiment of the present invention;

[0026] Figure 3 This is a plan view of the pile foundation under a building in a medium-risk area according to an embodiment of the present invention;

[0027] Figure 4 This is a plan view of the pile foundation under a building in a high-risk area according to an embodiment of the present invention;

[0028] In the above figures: 1. Bedrock; 2. Sliding surface; 3. Accumulation layer; 4. Long piles; 5. Short piles; 6. Low-risk area; 7. Medium-risk area; 8. High-risk area; 9. Buildings. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "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.

[0031] Refer to Figures 1 to 4 This embodiment provides a method for arranging pile foundations of densely packed buildings on a large landslide accumulation body, which includes the following steps:

[0032] S1. Conduct geological survey of the landslide deposits where the construction site is located and collect and calculate relevant parameters;

[0033] S2. Conduct stability analysis on the landslide accumulation, calculate the sliding force of the landslide and divide the dangerous area;

[0034] S3, under the buildings 9 in each dangerous area, arrange different numbers of rows of long piles 4 at different positions according to the size of the sliding force of the landslide, and the remaining rows of pile foundations are arranged with long piles 4 and short piles 5 at intervals;

[0035] S4, calculate whether the stability coefficient of the pile body after step S2 reinforcement and pile foundation bearing capacity, settlement meet the design requirements, if not, increase the pile diameter and / or pile length of long pile 4 and short pile 5 or increase the number of rows of long pile 4;

[0036] S5. Repeat step S3 until the stability coefficient of the landslide accumulation body, the pile foundation bearing capacity, and the settlement meet the design requirements.

[0037] Preferably, in step S1, a geological survey is conducted to collect the type, scale, thickness of the accumulation layer 3, type of sliding surface 2, spatial position of sliding surface 2, sliding main axis and physical and mechanical parameters of the rock and soil within the accumulation range; and indoor physical and mechanical properties tests are carried out on the rock and soil layer samples to calculate the sliding force and preliminarily determine the pile length, pile diameter and reinforcement ratio of the long pile 4 and the short pile 5.

[0038] In step S1, a geological survey is conducted to collect information such as the type and scale of the accumulation body, the thickness of the accumulation layer 3, the type and spatial position of the sliding surface 2, the main sliding axis, and the physical and mechanical parameters of the rock and soil within the accumulation body; and an indoor physical and mechanical performance test is performed on the rock and soil layer samples in accordance with the provisions of the national standard GB50330-2013 to calculate the sliding force and preliminarily determine various parameters such as the pile length, pile diameter, and reinforcement ratio of the long pile 4 and the short pile 5; the determination and calculation methods of the relevant parameters refer to the provisions of the national standard GB50330-2013;

[0039] Preferably, in step S2 , a stability analysis is performed on the deposited body, the dangerous areas of the deposited body are divided and their failure modes are identified, and the deposited body is divided into a high-danger area 8 , a medium-danger area 7 and a low-danger area 6 .

[0040] Among them, preferably, in step S2, the stability analysis of the accumulation body is performed, the dangerous areas of the accumulation body are divided and its failure mode is identified, and the accumulation body is divided into a high-risk area 8, a medium-risk area 7 and a low-risk area 6. The accumulation body in this embodiment presents a typical traction-type landslide failure mode, so the rear edge area of ​​the landslide accumulation body is divided into a low-risk area 6, the middle area is divided into a medium-risk area 7, and the front edge area is divided into a high-risk area 8.

[0041] Preferably, in step S3, the long pile 4 passes through the sliding surface 2 of the accumulation body and is embedded in the stable bedrock 1, and the embedding depth is not less than 2m, the bottom of the short pile 5 is above the sliding surface 2 of the accumulation body and is not embedded in the stable bedrock 1, the length of the short pile 5 is 1 / 2 to 4 / 5 of the length of the long pile 4, and the long pile 4 and the short pile 5 are both reinforced concrete circular cross-section piles.

[0042] Among them, in this example, the length of the 5 short piles is 3 / 5 of the length of the 4 long piles.

[0043] Preferably, in step S3, long piles 4 and short piles 5 are used to arrange building pile foundations in different areas of the accumulation body; under the buildings 9 in the low-risk area 6, the long piles 4 are continuously arranged in at least one row near the front edge of the landslide, and in several rows near the rear edge of the landslide, the long piles 4 and the short piles 5 are arranged at intervals; under the buildings 9 in the medium-risk area 7, the long piles 4 are continuously arranged in at least one row near the rear edge of the landslide, and in several rows near the front edge of the landslide, the long piles 4 and the short piles 5 are arranged at intervals; under the buildings 9 in the high-risk area 8, the long piles 4 are continuously arranged in at least two rows near the rear edge of the landslide, and in several rows near the front edge of the landslide, the long piles 4 and the short piles 5 are arranged at intervals.

[0044] Preferably, the distance between the long pile 4 and the adjacent short pile 5 or long pile 4 in the same row is 2 to 4 times the diameter of the short pile 5 .

[0045] Preferably, the distance between two adjacent rows of piles under the building 9 is 2 to 5 times the diameter of the short piles 5 .

[0046] Specifically, the numerical analysis and calculation in the above steps can be completed by using the ABAQUS finite element analysis software or other technologies in the existing technology. Based on the previous numerical simulation calculation results, a long and short pile model with relatively ideal results is selected to establish a three-dimensional geological model, and a comprehensive analysis of the corresponding pile type combination in terms of stress, settlement, pile body bending moment, etc. is performed.

[0047] Compared with the existing technology, 1. The present invention divides the danger level of the accumulation body into zones based on stability analysis, and adopts different long and short pile 5 combination layout schemes under the buildings 9 in different danger areas. The long piles 4 are embedded in the stable bedrock 1, which can effectively resist the landslide thrust and improve the stability of the landslide accumulation body. At the same time, it can control the settlement of the building 9. The short piles 5 can ensure the bearing capacity of the pile foundation. The long piles 4 and the short piles 5 complement each other and cooperate with each other to form a combined advantage, which can fully meet the stability requirements of the landslide accumulation body and the pile foundation bearing capacity and settlement requirements of the building 9; 2. The present invention avoids the waste caused by the large-scale use of anti-slip and load-bearing integrated deep piles in the existing conservative design by adopting a long-short combination and zoned pile layout scheme, greatly reduces the construction difficulty, thereby shortening the construction period and reducing the project cost. The proposed design method is simple to operate and is conducive to promotion.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for arranging pile foundations of densely packed buildings on a large landslide accumulation body, characterized in that: The method comprises the following steps: S1. Conduct geological survey of the landslide deposits where the construction site is located and collect and calculate relevant parameters; S2. Conduct stability analysis on the landslide accumulation, calculate the sliding force of the landslide and divide the dangerous area; S3. Under each building in the danger zone, arrange different rows of long piles in different positions according to the force of the landslide, and arrange the remaining rows of piles with long piles and short piles alternately; S4, calculate whether the stability coefficient and pile foundation bearing capacity and settlement of the pile body after reinforcement in step S3 meet the design requirements. If not, increase the pile diameter and / or pile length of the long pile and the short pile or increase the number of rows of the long pile; S5, repeat steps S3 and S4 until the stability coefficient of the landslide accumulation body and the pile foundation bearing capacity and settlement meet the design requirements; In step S3, long piles and short piles are used to arrange building pile foundations in different zones under buildings in different risk levels of the accumulation body; under buildings in low-risk zones, long piles are continuously arranged in at least one row near the leading edge of the landslide, and in several rows near the trailing edge of the landslide, long piles and short piles are arranged at intervals; under buildings in medium-risk zones, long piles are continuously arranged in at least one row near the trailing edge of the landslide, and in several rows near the leading edge of the landslide, long piles and short piles are arranged at intervals; under buildings in high-risk zones, long piles are continuously arranged in at least two rows near the trailing edge of the landslide, and in several rows near the leading edge of the landslide, long piles and short piles are arranged at intervals.

2. The method for arranging pile foundations of densely packed buildings on a large landslide accumulation body according to claim 1, characterized in that: In step S1, a geological survey is conducted to collect the type, scale, thickness of the accumulation layer, type of sliding surface, spatial position of the sliding surface, main axis of sliding, and physical and mechanical parameters of the rock and soil within the accumulation body; and indoor physical and mechanical performance tests are conducted on the rock and soil layer samples to calculate the sliding force and preliminarily determine the pile length, pile diameter, and reinforcement ratio of long and short piles.

3. The method for arranging pile foundations of densely packed buildings on a large landslide accumulation body according to claim 1, characterized in that: In step S2, a stability analysis is performed on the accumulation body, the dangerous areas of the accumulation body are divided and the failure modes thereof are identified, and the accumulation body is divided into a high-danger area, a medium-danger area and a low-danger area.

4. The method for arranging pile foundations of densely packed buildings on a large landslide accumulation body according to claim 1, characterized in that: In step S3, the long piles pass through the sliding surface of the accumulation body and are embedded in the stable bedrock, and the embedding depth is not less than 2m.

5. The method for arranging pile foundations of densely packed buildings on a large landslide accumulation body according to claim 4, characterized in that: In step S3, the bottom of the short pile is above the sliding surface of the accumulation body and is not embedded in the stable bedrock.

6. The method for arranging pile foundations of densely packed buildings on a large landslide accumulation body according to claim 5, characterized in that: The length of the short pile is 1 / 2 to 4 / 5 of the length of the long pile.

7. The method for arranging pile foundations of densely packed buildings on a large landslide accumulation body according to claim 6, characterized in that: The long piles and the short piles are both reinforced concrete piles with circular cross-sections.

8. The method for arranging pile foundations of densely packed buildings on a large landslide accumulation body according to claim 5, characterized in that: The distance between the long piles and the adjacent short piles or long piles in the same row is 2 to 4 times the diameter of the short piles.

9. The method for arranging pile foundations of densely packed buildings on a large landslide accumulation body according to claim 5, characterized in that: The distance between two adjacent rows of piles under a building is 2 to 5 times the diameter of the short piles.

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