Settlement control structure of waste slag filling body of residential area close to underpass tunnel

Abstract

The invention discloses a settlement control structure of a waste slag filling body of an underpass tunnel close to a residential district, the residential district is arranged on the right side of the tunnel, the distance between the residential district and the tunnel is gradually reduced and then gradually increased from front to back, the waste slag filling body area has a certain gradient, the slope toe of the waste slag filling body area is provided with an existing retaining wall, and the existing retaining wall is arranged on the right side of the tunnel. The rear end of the tunnel penetrates through the existing retaining wall; the settlement control structure comprises a plurality of anchoring piles and a plurality of rotary jet grouting piles which are distributed in a quincunx shape and are in a symmetrical isosceles triangle shape, and the depth of the rotary jet grouting piles is 1 m below the bed rock. The construction method is suitable for preventing sedimentation of the waste slag filling body penetrating through an underpass tunnel and penetrating through an adjacent residential area, the stability of the stratum of the waste slag filling body area can be effectively guaranteed through anchoring pile slope protection and jet grouting pile reinforcement, and therefore sedimentation of the waste slag filling body area in the construction process is prevented.

Description

Technical Field

[0001] The invention belongs to the technical field of settlement control in railway tunnel construction, and in particular relates to a settlement control structure for a waste slag landfill body passing under a tunnel adjacent to a residential area. Background Art

[0002] The existence of slag landfill areas is mainly due to the need to accumulate solid waste generated by various human activities and natural processes. There are many new railways passing through the main urban areas of cities, and there will be situations where new railways pass through slag bodies and involve residential areas. At present, railways passing through slag landfill areas are usually ground-passing, so it is only necessary to ensure that the railway is stable and does not sink. For mountainous cities, slag landfill areas usually appear on slopes, and it is necessary not only to ensure the stability of the slag landfill area, but also to ensure the stability of the railway. In this regard, the two use different methods to achieve stability. For example, the slag landfill area adopts slope management, while the stability of the railway line only requires simple reinforcement on the conventional line.

[0003] However, when the railway passes under a spoil landfill area that is close to residential areas, it is necessary not only to ensure that no settlement occurs during tunnel construction, but also to ensure that no settlement occurs between the residential area and the spoil landfill area. The overall construction environment is complex and there is no specific settlement control structure. Summary of the invention

[0004] The present invention proposes a settlement control structure for a waste landfill body passing through a tunnel adjacent to a residential area, which can achieve settlement control of the waste landfill body passing through a tunnel adjacent to a residential area.

[0005] To this end, the technical solution adopted by the present invention is: a settlement control structure of a waste landfill under a tunnel near a residential area, the right side of the tunnel is a residential area, and the distance between the residential area and the tunnel from front to back first gradually decreases and then gradually increases, the waste landfill area has a certain slope, and an existing retaining wall is arranged at the foot of the slope of the waste landfill area, and the rear end of the tunnel passes through the existing retaining wall; the settlement control structure includes a plurality of anchor piles and a plurality of symmetrical isosceles triangle jet piles arranged in a plum blossom shape, and the depth of the jet piles is The depth is 1m below the bedrock; in the section where the tunnel passes through the existing retaining wall, the anchor piles are set in the spoil landfill area on the right side of the tunnel, and the net distance from the anchor pile body to the tunnel excavation contour line in this section is between 3.4-10m; in the section where the tunnel is located on the right side of the existing retaining wall, the anchor piles are set in the spoil landfill area on the left side of the tunnel, and the net distance from the anchor pile body to the tunnel excavation contour line in this section is between 0.9-15m, and the net distance to the existing retaining wall is between 2.1-7.8m, and the construction sequence of the anchor piles is carried out from bottom to top according to the spoil landfill area.

[0006] As a preference in the above solution, the jet grouting piles are arranged in three areas. The first area is located at the position where the waste filling body area is close to the intersection of the tunnel and the existing retaining wall. In this area, the range where the jet grouting piles are arranged is within 2.74 m on each side of the tunnel lining contour line, and the height is within 5.0 m outside the outer contour line of the arch crown lining. The second area is within the section with the smallest distance between the tunnel and the residential area. In this area, the range where the jet grouting piles are arranged is between 2.74 m outside the left tunnel lining contour line and 5.04 m outside the right tunnel lining contour line, and the height is within 5.0 m outside the outer contour line of the arch crown lining. The third area is from the end of the second area to the tunnel leaving the waste filling body area. In this area, the range where the jet grouting piles are arranged is within 2.74 m on each side of the tunnel lining contour line, and the height is within 5.0 m outside the outer contour line of the arch crown lining.

[0007] Further preferably, for the jet grouting piles within the range of 2.29 - 5.04 outside the right lining contour line in the second area, after jetting to the ground, a reinforced concrete crown beam is provided by inserting steel flower pipes, and the construction sequence of the reinforced concrete crown beam is carried out in the direction away from the residential area.

[0008] Further preferably, the front end of the tunnel obliquely passes through the existing culvert, and the rear end of the existing culvert extends to the front end of the existing retaining wall. The intersection area between the tunnel and the existing culvert is reinforced by grouting with sleeve valves, and the hole positions on both sides of the existing culvert are arranged in the form of one row of vertical holes, two rows of inclined holes, and three rows of inclined holes, with the vertical holes close to the existing culvert.

[0009] Further preferably, the minimum interval between adjacent anchor piles is between 2.53 - 3 m.

[0010] Further preferably, the tunnel is excavated by machinery, the construction method adopts the three - bench method with temporary cross braces, the lining type adopts the Ⅴc - type composite lining, and when the waste invades the tunnel section, large arch feet are additionally provided at the upper bench construction.

[0011] The beneficial effects of the present invention: It is applicable to preventing settlement of the waste filling body when the under - passing tunnel passes through the area near the residential area. The anchor piles are arranged at the existing retaining wall for blocking the waste filling body area, enabling the protection of the waste filling body area with a slope. And jet grouting piles are also provided for ground reinforcement, and sleeve valve pipes are provided for underground reinforcement when passing through the culvert. Therefore, it can effectively ensure the stability of the stratum in the waste filling body area, thereby preventing settlement in the waste filling body area during the construction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a top view of the distribution of the jet grouting piles in this embodiment.

[0013] Figure 2 It is a top view of the distribution of the anchor piles in this embodiment.

[0014] Figures 3 - 7 is Figure 2 the corresponding cross-sectional schematic diagram.

[0015] Figure 8 This is the elevation view of the distribution of anchor piles in the section where the tunnel passes through the existing retaining wall in this embodiment.

[0016] Figure 9 This is the elevation view of the distribution of anchor piles in the section where the tunnel is located on the right side of the existing retaining wall in this embodiment.

[0017] Figure 10 This is the cross-sectional view of the distribution of jet grouting piles in the first area in this embodiment.

[0018] Figure 11 This is the cross-sectional view of the distribution of jet grouting piles in the second area in this embodiment.

[0019] Figure 12 This is the cross-sectional view of the distribution of jet grouting piles in the third area in this embodiment.

[0020] Figure 13 This is the top view of the distribution of sleeve valve pipe grouting reinforcement in this embodiment.

[0021] Figure 14 This is the cross-sectional view of the distribution of sleeve valve pipe grouting reinforcement in this embodiment.

[0022] Reference numerals: tunnel - 1, residential area - 2, waste dump filling area - 3, existing retaining wall - 4, existing culvert - 5. Specific implementation manner

[0023] The present invention will be further described below through embodiments in conjunction with the accompanying drawings:

[0024] As Figures 1 - 14 shown, a settlement control structure for a waste dump filling body adjacent to a residential area under a tunnel, where the right side of the tunnel 1 is a residential area, and the distance between the residential area 2 and the tunnel gradually decreases first and then gradually increases from front to back. The waste dump filling area 3 has a certain slope, and an existing retaining wall 4 is provided at the toe of the slope of the waste dump filling area. The rear end of the tunnel passes through the existing retaining wall, and an existing culvert 5 for drainage is provided at the front end of the existing retaining wall, and the tunnel obliquely passes through the existing culvert.

[0025] The settlement control structure includes a plurality of anchor piles and a plurality of jet grouting piles provided. Among them, the anchor piles are arranged in the waste dump filling area with a certain slope for slope protection, the jet grouting piles are arranged in a plum blossom shape and are symmetric isosceles triangles for ground reinforcement, and the depth of the jet grouting piles is 1.0 m below the bedrock.

[0026] In the section where the tunnel passes through the existing retaining wall, the anchor piles are set in the waste filling area on the right side of the tunnel. The clear distance between the anchor pile body and the tunnel excavation contour line in this section ranges from 3.4 m to 10 m. In the section where the tunnel is on the right side of the existing retaining wall, the anchor piles are set in the waste filling area on the left side of the tunnel, that is, between the waste filling area and the tunnel. The clear distance between the anchor pile body and the tunnel excavation contour line in this section ranges from 0.9 m to 15 m, and the clear distance to the existing retaining wall ranges from 2.1 m to 7.8 m. Preferably, the construction sequence of the anchor piles is carried out from bottom to top in the waste filling area.

[0027] Since the distance between the residential area and the tunnel gradually decreases first and then gradually increases from front to back, preferably, the jet grouting piles are set in three areas. The first area is located at the position where the waste filling area is close to the intersection of the tunnel and the existing retaining wall. In this area, the setting range of the jet grouting piles is within 2.74 m on both the left and right sides of the tunnel lining contour line, and the height is within 5.0 m outside the outer contour line of the arch crown lining. The second area is in the section where the interval distance between the tunnel and the residential area is the smallest. In this area, the setting range of the jet grouting piles is between 2.74 m outside the left tunnel lining contour line and 5.04 m outside the right tunnel lining contour line, and the height is within 5.0 m outside the outer contour line of the arch crown lining. The third area is from the end of the second area to the tunnel leaving the waste filling area. In this area, the setting range of the jet grouting piles is within 2.74 m on both the left and right sides of the tunnel lining contour line, and the height is within 5.0 m outside the outer contour line of the arch crown lining.

[0028] Among them, after the jet grouting piles in the first area, the third area and the second area except for the range of 2.29 - 5.04 m outside the right tunnel lining contour line are constructed, the leading holes where the grout does not spray and the grout overflow is not filled are backfilled with 1:1.5 cement mortar to the hole top. When the jet grouting piles within the range of 2.29 - 5.04 m outside the right lining contour line in the second area are sprayed to the ground, a reinforced concrete crown beam is set by inserting steel flower pipes, and the construction sequence of the reinforced concrete crown beam is carried out in the direction away from the residential area.

[0029] In the area where the tunnel intersects with the existing culvert, grouting reinforcement is carried out through sleeve valves, and the hole positions on both sides of the existing culvert are arranged in the form of one row of vertical holes, two rows of inclined holes, and three rows of inclined holes, with the vertical holes close to the existing culvert.

[0030] To control the settlement of the tunnel, for the tunnel passing through the waste filling area, mechanical excavation is adopted, and the construction method is the three - step plus temporary cross - brace step method. The lining type is the Ⅴc type composite lining. When the waste invades the tunnel section, large arch feet are added at the upper bench construction.

[0031] This settlement control structure has been specifically implemented. The tunnel under implementation is a double-track large-section tunnel. The section of the tunnel passing through the waste dump filling area is 295 m, specifically the section from DK6+990 to DK7+285. The buried depth of the tunnel is 9 - 24 m, and the closest horizontal distance from the tunnel side to the residential area is 35 m. The upper layer of the stratum through which the tunnel passes is artificial waste soil, and the lower layer is mudstone intercalated with sand. The slope height of the waste dump filling area is 10 - 30 m. A transverse gravity retaining wall is set at the slope foot of the waste dump filling area, a drainage ditch is set at the bottom of the retaining wall, and a circular pipe culvert is set downstream to the natural ditch. The tunnel also passes through the circular pipe culvert, and the included angle between the circular pipe culvert and the tunnel is about 21°. Among them, the section from DK237.8 to DK7+285 passes through the circular pipe culvert.

[0032] As Figures 2 - 9 shown, 25 anchor piles are designed in the section from DK6+990.65 to DK7+185.33. The pile diameter is 1.8 m, the minimum pile spacing is 2.53 m - 3 m, the pile length is 16 m - 28 m, and the pile body is all cast with C35 concrete. Among them, 6 piles are set on the right side of the line in the section from DK6+990.56 to DK7+015.6. The net distance from the pile body to the tunnel excavation contour line is about 3.4 m - 10 m, as Figure 8 shown. 19 anchor piles are set on the left side of the line in the section from DK7+044.97 to DK7+185.33. The net distance from the pile body to the tunnel excavation contour line is about 0.9 m - 15 m, and the net distance to the existing retaining wall of the slope is about 2.1 m - 7.8 m, as Figure 9 shown.

[0033] As Figure 1 、 10 、11、12、13 shown, all jet grouting piles are φ600 mm high-pressure jet grouting piles, and the spacing is 1.2 m × 1.2 m. The first area is the section from DK7+040 to DK7+065, where the drilling depth is 12.93 - 21.5 m, and among them Figure 10 is the cross-sectional view of DK7+58. The second area is the section from DK7+098 to DK7+162.6, where the drilling depth is 20.10 - 34.14 m. The high-pressure jet grouting piles (a total of 5 rows) within 2.29 - 5.04 m outside the right lining contour line are jetted to the original ground and then the φ89 mm × 6 mm steel pipe with holes is inserted with the cooperation of an excavator. There is a reinforced concrete capping beam at the top, with a length of 10 - 20 m for each section, a height of 0.5 m, a width of 2.622 m, and the concrete grade is C30. After the construction of the capping beam is completed, the top is backfilled with C20 concrete. Among them Figure 11 is the cross-sectional view of DK7+098. The third area is the section from DK7+162.6 to DK7+285, where the drilling depth is 20.10 - 34.14 m, and among them Figure 12 is the cross-sectional view of DK7+238.

[0034] AsFigure 13 , 14 As shown in 14 , the minimum clear distance between the tunnel top and the culvert bottom is about 2.8 m. The bottom of the existing drainage culvert in this section is reinforced by grouting with sleeve valves. The φ50 mm plastic sleeve valves are used, and the grouting is carried out with ordinary 425 Portland cement slurry. The hole layout forms on both sides of the culvert are in three ways: the closest row of vertical holes, the second row of inclined holes (horizontal angle about 75°), and the third row of inclined holes (horizontal plane angle about 60°). Among them, Figure 14 is the cross-section diagram of DK7+258.

[0035] For the excavation of the section from DK6+990 to DK7+285, mechanical excavation is adopted. According to the surrounding rock conditions, when the rock mass strength is high and the face integrity is good, hydraulic breaker + peripheral shock-absorbing holes are used for excavation; when the surrounding rock strength is not high and the core soil does not need to be reserved at the face, roadheader excavation can be adopted; when the face enters the slag area, the upper bench core soil is reserved, and excavator + hydraulic breaker + manual cooperation are used. The construction method adopts the three-bench method with temporary cross braces, and the lining type adopts the Ⅴc type composite lining. The full ring of the strengthened support uses I22a steel frames with a spacing of 0.6 m per frame. The advanced support uses medium pipe roofs with a diameter of 76 mm, 40 roots per ring, a longitudinal spacing of 6 m, and a single root length of 10 m. For the muck pile invading the tunnel section, large arch feet are added at the upper bench construction to ensure that the upper bench arch frame does not sink, and thus ensure the stability of the tunnel settlement.

Claims

1. A settlement control structure for a waste landfill near a residential area under a tunnel, characterized by: The right side of the tunnel is a residential area, and the distance between the residential area and the tunnel gradually decreases from front to back and then gradually increases. The spoil landfill area has a certain slope, and an existing retaining wall is set at the foot of the slope of the spoil landfill area. The rear end of the tunnel passes through the existing retaining wall. The settlement control structure includes a plurality of anchor piles and a plurality of jet grouting piles arranged in a plum blossom shape and in a symmetrical isosceles triangle, the depth of the jet grouting piles being 1 m below the bedrock; in the section where the tunnel passes through the existing retaining wall, the anchor piles are arranged in the slag landfill area on the right side of the tunnel, and the net distance between the anchor pile body and the tunnel excavation contour line in this section is between 3.4-10 m; in the section where the tunnel is located on the right side of the existing retaining wall, the anchor piles are arranged in the slag landfill area on the left side of the tunnel, and the net distance between the anchor pile body and the tunnel excavation contour line in this section is between 0.9-15 m, and the net distance to the existing retaining wall is between 2.1-7.8 m, and the construction sequence of the anchor piles is carried out from bottom to top according to the slag landfill area.

2. According to claim 1, a settlement control structure for a waste landfill near a residential area under a tunnel, characterized in that: The rotary jet grouting piles are arranged in three areas. The first area is located in the spoil landfill area near the intersection of the tunnel and the existing retaining wall. The range of the rotary jet grouting piles in this area is within 2.74m on both sides of the tunnel lining contour line, and the height is within 5.0m outside the outer contour line of the arch lining; the second area is the section with the shortest distance between the tunnel and the residential area. The range of the rotary jet grouting piles in this area is between 2.74m outside the left tunnel lining contour line and 5.04m outside the right tunnel lining contour line, and the height is within 5.0m outside the outer contour line of the arch lining; the third area is from the end of the second area to the tunnel and leaving the spoil landfill area. The range of the rotary jet grouting piles in this area is within 2.74m on both sides of the tunnel lining contour line, and the height is within 5.0m outside the outer contour line of the arch lining.

3. According to claim 2, a settlement control structure for a waste landfill near a residential area under a tunnel, characterized in that: The jet grouting piles in the second area within the range of 2.29-5.04 outside the right lining contour line are provided with reinforced concrete cap beams by inserting steel flower pipes after being sprayed to the ground, and the construction sequence of the reinforced concrete cap beams is carried out in the direction away from the residential area.

4. According to claim 1, a settlement control structure for a waste landfill near a residential area under a tunnel, characterized in that: The front end of the tunnel obliquely passes through the existing culvert, and the rear end of the existing culvert extends to the front end of the existing retaining wall. The intersection area between the tunnel and the existing culvert is reinforced by sleeve valve pipe grouting, and the holes on both sides of the existing culvert are arranged in the form of one row of vertical holes, two rows of oblique holes, and three rows of oblique holes, among which the vertical holes are close to the existing culvert.

5. The settlement control structure of the waste landfill near the residential area under the tunnel according to claim 1, characterized in that: The minimum spacing between adjacent anchor piles is between 2.53-3m.

6. The settlement control structure of the waste landfill near the residential area under the tunnel according to claim 1, characterized in that: The tunnel is excavated mechanically, the construction method adopts the three-step plus temporary cross-bracing step method, and the lining type adopts the VC type composite lining. When the waste slag invades the section of the tunnel, a large arch foot is added at the upper step construction site.

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