Anti-seepage structure for engineering close to dike foundation

Abstract

The utility model discloses a close dike foundation engineering anti-seepage structure which comprises a bearing platform located below the ground and above a permeable layer and a plurality of drilling piles located at the bottom of the bearing platform, each drilling pile is evenly provided with a plurality of high-pressure jet grouting piles in the circumferential direction, the side, facing the drilling pile, of each high-pressure jet grouting pile is meshed with the drilling pile, and the side, facing the permeable layer, of each high-pressure jet grouting pile is meshed with the drilling pile. The adjacent high-pressure jet grouting piles are meshed together, the bottoms of the high-pressure jet grouting piles are arranged above the permeable layer, and the bearing platform, the drilling piles and the high-pressure jet grouting piles form an integral structure. The anti-seepage structure can effectively reduce water and sand gushing risks caused by construction near a levee, effectively guarantees the foundation anti-seepage quality, is good in overall anti-seepage effect, and can be widely applied to the technical field of bridge foundation anti-seepage construction.

Description

Technical Field

[0001] The utility model relates to the technical field of bridge foundation anti-seepage construction, in particular to an anti-seepage structure for foundation engineering adjacent to a levee. Background Art

[0002] In recent years, during the flood season of the Yangtze River, especially after the Yangtze River flood in 1998, the society has increasingly increased its protection requirements for the construction of embankments near the Yangtze River. With the construction of modern urban transportation, construction projects combining riverside expressways, urban expressways and public recreational water platforms are common. In the foundation construction of this type of bridge engineering, the bored pile foundation often needs to pass through the impermeable layer deep in the foundation, and the excavation of the foundation pit will also disturb the original soil, which is easy to cause seepage and pipe burst channels near the embankment, which has a great impact on the flood control function of the embankment, and necessary anti-seepage measures need to be taken. Common anti-seepage measures for bridge foundation engineering mostly use cement mixing piles between piles to stop water or cement slurry injection between piles. However, this method has poor overall impermeability, and the cost of cement slurry grouting is high and the effect is uncontrollable. Therefore, it is necessary to study a new type of comprehensive anti-seepage system. Utility Model Content

[0003] The purpose of the utility model is to overcome the deficiencies of the above-mentioned background technology and to provide an anti-seepage structure for foundation engineering near a levee, so that the risk of water and sand gushing caused by construction near the levee can be effectively reduced, the quality of foundation anti-seepage is effectively guaranteed, and the overall anti-seepage effect is good.

[0004] The utility model provides an anti-seepage structure for a foundation engineering adjacent to a levee, comprising a cap located below the ground and above a permeable layer, and a plurality of bored piles located at the bottom of the cap, each bored pile being evenly distributed with a plurality of high-pressure rotary jet piles along the circumference, each high-pressure rotary jet pile being engaged with the bored pile on one side facing the bored pile, adjacent high-pressure rotary jet piles being engaged with each other, the bottom of the high-pressure rotary jet pile being arranged above the permeable layer, and the cap, the bored piles and the high-pressure rotary jet piles forming an integral structure.

[0005] In the above technical solution, the distance between the side of each high-pressure jet grouting pile away from the bored pile and the outer circumference of the bored pile is 20 cm.

[0006] In the above technical solution, a clay layer is provided in the foundation pit around the foundation platform, and a drainage blind ditch is provided at the bottom of the clay layer for draining groundwater flowing in the direction of the groundwater.

[0007] In the above technical solution, a plurality of anti-filter geotextiles are provided along the circumferential direction on the side wall of the pedestal and the top surface of the clay layer outside the pedestal, and the plurality of anti-filter geotextiles form an annular structure as a whole, wherein a portion of each anti-filter geotextile is attached to the side wall of the pedestal and another portion is attached to the top surface of the clay layer outside the pedestal, the plurality of anti-filter geotextiles attached to the side wall of the pedestal form a vertical annular structure, and the plurality of anti-filter geotextiles attached to the top surface of the clay layer outside the pedestal form a horizontal annular structure.

[0008] In the above technical solution, the distance between the anti-filtration geotextile with a horizontal ring structure and the top surface of the foundation is 1m.

[0009] In the above technical solution, the distance between the outer edge of the anti-filtration geotextile with a horizontal ring structure and the side wall of the foundation is 2m.

[0010] In the above technical solution, adjacent anti-filter geotextiles overlap each other, wherein two sides of one anti-filter geotextile are located above the side edges of adjacent anti-filter geotextiles, forming a herringbone overlap.

[0011] The utility model has the following beneficial effects:

[0012] The utility model adopts a comprehensive treatment method of setting high-pressure jet-jet piles around the bored piles to stop water + wrapping the outer surface of the foundation with anti-filtration geotextile to prevent seepage, forming an overall foundation anti-seepage system. The anti-filtration geotextile used has the characteristics of light weight, good overall continuity, convenient construction, high tensile strength, and corrosion resistance. The comprehensive anti-seepage treatment of the foundation near the levee can effectively reduce the risk of water and sand gushing caused by construction near the levee, the quality of foundation anti-seepage is effectively guaranteed, and the impact of foundation construction near the levee on the levee is reduced. The overall anti-seepage effect is good, and it has good social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the elevation structure of the utility model of the anti-seepage structure of the adjacent embankment foundation project;

[0014] Figure 2 It is a cross-sectional schematic diagram of the anti-seepage structure of the utility model near the dike foundation project;

[0015] Figure 3 It is a structural schematic diagram of bored piles and high-pressure jet grouting piles in the anti-seepage structure of the foundation engineering near the embankment of the utility model. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but the embodiments should not be construed as limiting the present invention.

[0017] like Figure 1The anti-seepage system of the foundation engineering near the embankment shown in the figure comprises bored piles 1, high-pressure rotary jet piles 2, groundwater direction 3, cap 4, ground 8, and permeable layer 9; the grouting pipe of the high-pressure rotary jet pile 2 (not shown in the figure) is inserted into the clay layer 7 or the silty clay layer 7 above the permeable layer 9 to form a consolidation body, so that the bored pile 1 completely closes the water gushing channel formed by the disturbance of the original soil layer on the surface above the permeable layer 9; the high-pressure rotary jet pile 2 is used to stop the water around the periphery of the bored pile 1; when the cap 4 is constructed, the redundant pile head is broken, so that the cap 4, the high-pressure rotary jet pile 2, and the bored pile 1 are connected into a whole;

[0018] like Figure 2 The anti-seepage system of the foundation engineering near the embankment shown includes a groundwater direction 3, a cap 4, a filter geotextile 5, a drainage blind ditch 6, a clay layer 7, and a ground 8; the foundation pits on both sides of the cap 4 are backfilled with clay to form a clay layer 7, and a drainage blind ditch 6 is provided under the clay layer 7 in the foundation pit; the groundwater flowing along the groundwater direction 3 is discharged through the drainage blind ditch 6; and the filter geotextile 5 is pasted around the top surface of the cap 4.

[0019] like Figure 3 As shown, the high-pressure jet grouting pile 2 is consolidated around the bored pile 1 to form a circle of cylindrical pile bodies that interlock with each other.

[0020] Preferably, the high-pressure jet-jet pile 2 expands outward by 20 cm along the outline of the bored pile 1 .

[0021] Preferably, the top of the high-pressure jet-jet pile 2 should be 50 cm higher than the bottom surface of the cap.

[0022] Preferably, the longitudinal and lateral deviations of the high-pressure jet grouting pile 2 are no more than 50 mm, the jet grouting pipe performs the jetting operation from bottom to top, and the lifting speed of the grouting pipe should be less than 0.14 m / min. The jetting process is continuous and uniform. The high-pressure jet grouting pile 2 uses coring to check the integrity of the pile foundation.

[0023] Preferably, the foundation pits on both sides of the cap 4 are backfilled with clay 7 in layers, the thickness of the backfill is not more than 25 mm, and the backfill compaction is not less than 95%. The clay is selected from high-quality silt, the organic mixture content is not more than 3%, the plasticity index IP=10~17, the permeability coefficient is not more than 10-5cm / s, and the moisture content is allowed to deviate by ±3%.

[0024] Preferably, the anti-filtration geotextile 5 has a specification of 350g / ㎡ and has the characteristics of light weight, good overall continuity, convenient construction, high tensile strength, and corrosion resistance.

[0025] Preferably, when the foundation pit clay layer 7 is backfilled to 1 m below the top surface of the cap 4, the anti-filtration geotextile 5 is laid, and the anti-filtration geotextile 5 is unfolded from top to bottom in the length direction, and a proper deformation margin is left.

[0026] Preferably, the anti-filter geotextile 5 is pasted on the side of the base 4 with KS hot melt adhesive. The hot melt adhesive is heated to 150-180°C in a crucible and evenly applied to the side of the base 4 with a metal stick, with a brushing length of 50 cm each time. After the brushing is completed, the anti-filter geotextile 5 is pasted on the base 4 and gently tapped with a rubber hammer to ensure that it is firmly pasted.

[0027] Preferably, the anti-filtration geotextile 5 extends horizontally 2m around the base 4 and is overlapped in a herringbone shape with a overlap length of 50cm.

[0028] The construction method of this embodiment is as follows: firstly, the bored pile 1 is constructed, and the relative relationship between the permeable layer and the impermeable layer in the bottom layer of the foundation geology is determined by geological survey. The high-pressure rotary jet pile 2 is used to stop the water around the pile, that is, after the bored pile 1 is constructed, the grouting pipe with a special nozzle is inserted into the clay layer 7 or the silty clay layer 7 above the permeable layer 9, and then the cement slurry is ejected from the nozzle in the form of a high-pressure flow to impact and cut the soil. Under the powerful power of the high-pressure jet flow, the soil body is damaged in strength, and the soil particles are peeled off from the soil layer and stirred with the cement slurry to form a mixed slurry. A part of the fine particles emerge from the ground with the mixed slurry, and the remaining soil particles are rearranged in a planned manner according to a certain slurry-soil ratio and mass size under the impact force of the jet, centrifugal force and gravity. In this way, grouting is continuously sprayed from bottom to top. After the mixed slurry solidifies, a consolidation body with a certain strength is formed in the soil layer, and a circle of cylindrical pile bodies that interlock with each other are consolidated around the pile, which has good strength and impermeability, so that the bored pile 1 completely closes the water gushing channel formed by the disturbance of the original soil layer on the surface above the permeable layer. The pile top elevation of the high-pressure rotary jet pile 2 is 0.5m higher than the bottom of the cap. When the cap 4 is constructed, the excess pile head is broken off, so that the cap 4 and the high-pressure rotary jet pile 2 are connected as a whole. After the construction of the cap 4 is completed, in order to reduce the adverse effects caused by the excavation of the foundation pit and increase the impermeability of the foundation pit backfill, it is necessary to use high-quality clay foundation pit backfill and compact it in layers to form a clay layer 7 as required, and lay a layer of anti-filtration geotextile 5 around the top surface of the cap 4, and extend it outward for a certain distance to form an impermeable layer. The anti-filtration geotextile 5 replaces the traditional granular material to build the anti-filtration layer, and has the characteristics of light weight, good overall continuity, convenient construction, high tensile strength, corrosion resistance, etc. The anti-filtration geotextile 5 is tightly fitted with the foundation 4 structure to form another anti-seepage defense line.

[0029] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0030] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. An anti-seepage structure for a foundation project near a dike, comprising a cap (4) located below the ground (8) and above a permeable layer (9) and a plurality of bored piles (1) located at the bottom of the cap (4), characterized in that: Each bored pile (1) is evenly distributed with a plurality of high-pressure jet grouting piles (2) along the circumference, and each high-pressure jet grouting pile (2) is engaged with the bored pile (1) on one side facing the bored pile (1), and adjacent high-pressure jet grouting piles (2) are engaged with each other, and the bottom of the high-pressure jet grouting pile (2) is arranged above the permeable layer (9), and the cap (4), the bored pile (1) and the high-pressure jet grouting pile (2) form an integral structure.

2. The anti-seepage structure of the foundation engineering near the embankment according to claim 1 is characterized by: The distance between the side of each high-pressure jet grouting pile (2) away from the bored pile (1) and the outer circumference of the bored pile (1) is 20 cm.

3. The anti-seepage structure of the foundation engineering near the embankment according to claim 2 is characterized by: A clay layer (7) is provided in the foundation pit around the cap (4), and a drainage blind ditch (6) for draining groundwater flowing along the groundwater direction (3) is provided at the bottom of the clay layer (7).

4. The anti-seepage structure of the foundation engineering near the embankment according to claim 3 is characterized by: A plurality of anti-filter geotextiles (5) are provided along the circumferential direction on the side walls of the pedestal (4) and the top surface of the clay layer (7) outside the pedestal (4), and the plurality of anti-filter geotextiles (5) form an annular structure as a whole, wherein a portion of each anti-filter geotextile (5) is attached to the side walls of the pedestal (4) and another portion is attached to the top surface of the clay layer (7) outside the pedestal (4), the portions of the anti-filter geotextiles (5) attached to the side walls of the pedestal (4) form a vertical annular structure, and the portions of the anti-filter geotextiles (5) attached to the top surface of the clay layer (7) outside the pedestal (4) form a horizontal annular structure.

5. The anti-seepage structure of the foundation engineering near the embankment according to claim 4 is characterized by: The distance between the anti-filtration geotextile (5) in a horizontal ring structure and the top surface of the foundation (4) is 1 m.

6. The anti-seepage structure of the foundation engineering near the embankment according to claim 5 is characterized by: The distance between the outer edge of the anti-filter geotextile (5) in a horizontal ring structure and the side wall of the base (4) is 2m.

7. The anti-seepage structure of the foundation engineering near the embankment according to claim 6, characterized in that: Adjacent anti-filter geotextiles (5) overlap each other, wherein two sides of one anti-filter geotextile (5) are located above the side edges of an adjacent anti-filter geotextile (5), forming a herringbone-shaped overlap.

Images