Construction method of support pile row crossing underground cavity region

Abstract

The present application relates to a kind of construction methods of retaining row piles crossing underground cavity area, comprising the following steps: using drilling backfill method to carry out backfill treatment to underground cavity area, the drilling range is greater than the two sides of the retaining row piles to be crossed each 2m, the drilling depth is greater than the bottom of the underground cavity area 2m;At each pile position of the retaining row piles to be crossed, hole is opened and each pile hole is formed;Before the construction of each pile hole is carried out, anti-side pressure steel casing is respectively arranged in the backfill soil on the two sides of the corresponding pile hole, and the anti-side pressure steel casing is recycled after the construction of cast-in-place pile is completed.The construction method of retaining row piles of the present application, by drilling backfill method, pretreats underground cavity, ensures the quality of cast-in-place pile hole forming and pile forming, and the process is simple, low in cost.

Description

Technical Field

[0001] This invention relates to the field of building envelope construction, and in particular to a method for constructing retaining piles that traverse underground cavities. Background Technology

[0002] Drilled cast-in-place piles are a common type of retaining structure support pile, widely used in engineering construction. In areas without groundwater and with favorable geological conditions, dry drilling is generally used, resulting in good pile quality. However, under special geological conditions, such as the presence of underground caverns, dry drilling technology cannot guarantee pile quality. The process is prone to borehole collapse, causing concrete to dissipate along the underground caverns during the pouring of the cast-in-place pile, resulting in significant concrete waste and substantial pile quality defects. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a method for constructing retaining piles that traverse underground cavities. By pre-treating the underground cavities through drilling and backfilling, the method ensures the quality of the cast-in-place piles and the overall pile quality. The process is simple and low-cost.

[0004] This invention is achieved through the following scheme: a method for constructing retaining piles traversing underground cavities, comprising the following steps:

[0005] The underground cavity area was backfilled by drilling and backfilling. The drilling range was 2m larger than both sides of the retaining piles to be crossed, and the drilling depth was 2m larger than the bottom slab of the underground cavity area.

[0006] Drill holes at each pile location of the retaining wall piles to be penetrated and form each pile hole;

[0007] Before the construction of cast-in-place piles in each pile hole, anti-lateral pressure steel casings are installed in the backfill soil on both sides of the corresponding pile hole, and the anti-lateral pressure steel casings are retrieved after the construction of the cast-in-place piles is completed.

[0008] A further improvement of the construction method for retaining piles traversing underground cavities in this invention is that, when backfilling the underground cavities, a skip-hole method is used for drilling.

[0009] A further improvement of the construction method for retaining piles traversing underground cavities in this invention is that, when backfilling the underground cavities, the portion from the bottom slab of the underground cavity to the borehole opening is backfilled first, and then the portion from the top slab of the underground cavity to the ground surface is backfilled.

[0010] A further improvement of the construction method for retaining piles in the present invention for traversing underground cavities is that, when backfilling the portion from the bottom slab to the borehole opening in the underground cavity area, plain soil is used for backfilling, and rotary drilling is used for compaction during the backfilling process. At the same time, water immersion deposition is used to increase the density of the backfill soil.

[0011] A further improvement of the construction method for retaining piles traversing underground cavities in this invention is that the skip-pile method is used to open holes and form pile holes at each pile location of the retaining piles to be traversed.

[0012] A further improvement of the construction method for retaining piles traversing underground cavity areas in this invention is that the bottom end of the anti-lateral pressure steel casing is at least 0.5m lower than the bottom slab of the underground cavity area, and the top end of the anti-lateral pressure steel casing is at least 0.5m higher than the top slab of the underground cavity area.

[0013] A further improvement of the construction method for retaining piles in the present invention for traversing underground cavities is that, when setting up anti-lateral pressure steel casings, the casing pile holes are first formed, and then the anti-lateral pressure steel casings are lowered; after the anti-lateral pressure steel casings are retrieved, the casing pile holes are backfilled.

[0014] A further improvement of the construction method for retaining piles traversing underground cavities in this invention is that the diameter of the anti-lateral pressure steel casing is not less than the diameter of the corresponding pile hole.

[0015] This invention pre-treats underground cavities by drilling and backfilling, ensuring the quality of the cast-in-place pile hole and pile formation. Compared with large-area excavation and backfilling, the process is simple, requires less construction resources, and effectively saves construction costs. For underground cavities with large burial depths, the benefits are even more significant. Attached Figure Description

[0016] Figure 1 A flowchart of the construction method for retaining piles traversing underground cavities according to the present invention is shown.

[0017] Figure 2 A schematic diagram of the plan layout of the retaining piles of the present invention passing through the underground cavity area is shown.

[0018] Figure 3 A schematic planar view of the borehole area for borehole backfilling according to the present invention is shown.

[0019] Figure 4 A cross-sectional schematic diagram of the first drilled hole of the present invention is shown.

[0020] Figure 5 A cross-sectional schematic diagram of the first borehole after backfilling is shown.

[0021] Figure 6 A schematic cross-sectional view of all boreholes after backfilling according to the present invention is shown.

[0022] Figure 7 This diagram shows a cross-sectional view of the steel casing installed before the construction of cast-in-place piles at the pile hole, according to the present invention. Detailed Implementation

[0023] To address the issue that dry drilling techniques cannot guarantee pile quality in situations involving underground caverns, this invention provides a method for constructing retaining piles traversing underground cavities. This method pre-treats the underground cavities through drilling and backfilling, ensuring the quality of the cast-in-place piles. The process is simple and low-cost. The following detailed description, in conjunction with accompanying drawings, further illustrates this method for constructing retaining piles traversing underground cavities.

[0024] See Figures 1 to 7 As shown, a method for constructing retaining piles through an underground cavity includes the following steps:

[0025] Step 1: Backfill the underground cavity area 1 by drilling and backfilling. The drilling range is 2m larger than both sides of the retaining pile 2 to be crossed, and the drilling depth is 2m larger than the bottom slab of the underground cavity area.

[0026] Specifically, such as Figure 3 and Figure 4 As shown, there is a row of boreholes 3 on each side of the retaining pile 2. The bottom of the boreholes 3 is located 2m below the bottom slab of the underground cavity area 1. When backfilling the underground cavity area 1, a skip-hole method is used for drilling, and backfilling is carried out in two stages: first, backfilling is done from the bottom slab of the underground cavity area 1 to the borehole opening (i.e.,...). Figure 4 (The section from the top slab of underground cavity area 1 to the ground surface 4 is backfilled). Specifically: When backfilling the section from the bottom slab of underground cavity area 1 to the borehole opening, plain soil is used. This plain soil must be loose and uniform in texture, and large clumps of slag are strictly prohibited. During the backfilling process, rotary drilling is used for compaction to ensure dense backfilling. Simultaneously, water immersion deposition is used to increase the density of the backfill soil. When backfilling the section from the top slab of underground cavity area 1 to the ground surface 4, the backfill soil will first naturally accumulate within underground cavity area 1 until the backfill soil within underground cavity area 1 stops settling. Only then will the section from the top slab of underground cavity area 1 to the borehole opening 4 be backfilled. After the entire borehole 3 is backfilled, it forms the following shape: Figure 5 The backfill soil 5 shown is for the boreholes. Using the above backfilling method ensures effective sealing of the underground cavity area 1, thereby ensuring the quality of subsequent retaining pile drilling. Furthermore, the spacing between adjacent boreholes 3 should ensure that the space corresponding to the borehole area of ​​the underground cavity area 1 is completely filled with backfill soil. After all boreholes 3 within the borehole area are backfilled, a structure resembling […] will be formed. Figure 6 The backfill soil for the borehole shown is 5.

[0027] Step 2: Drill holes at each pile location of the retaining pile 2 to form pile holes 21. Specifically, after the underground cavity area is backfilled, the retaining piles are drilled using the skip-fill method to form pile holes 21.

[0028] Step 3, as follows Figure 7As shown, during the construction of cast-in-place piles, a steel cage needs to be placed in the pile hole 21 and then concrete is poured. In order to prevent the backfill soil that has been sealed from shifting due to the lateral pressure during the pouring of concrete, anti-lateral pressure steel casings 6 are installed in the backfill soil on both sides of the corresponding pile hole 21 before the construction of cast-in-place piles in each pile hole 21. After the construction of cast-in-place piles is completed, the anti-lateral pressure steel casings 6 are retrieved.

[0029] In this embodiment: the diameter of the anti-lateral pressure steel casing 6 is not less than the diameter of the corresponding pile hole 21, and the wall thickness of the anti-lateral pressure steel casing 6 is not less than 8mm; when setting the anti-lateral pressure steel casing 6, the casing pile hole is formed first, and then the anti-lateral pressure steel casing 6 is lowered, and when lowering, the bottom end of the anti-lateral pressure steel casing 6 is lower than the bottom plate of the underground cavity area 1 by at least 0.5m, and the top end of the anti-lateral pressure steel casing 6 is higher than the top plate of the underground cavity area 1 by at least 0.5m; after the anti-lateral pressure steel casing 6 is retrieved, the casing pile hole is backfilled.

[0030] This invention pre-treats underground cavities by drilling and backfilling, ensuring the quality of the cast-in-place pile hole and pile formation. Compared with large-area excavation and backfilling, the process is simple, requires less construction resources, and effectively saves construction costs. For underground cavities with large burial depths, the benefits are even more significant.

[0031] 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 method for constructing retaining piles traversing an underground cavity area, characterized in that, Including the following steps: The underground cavity area is backfilled by drilling and backfilling. The drilling range is 2m larger than the two sides of the retaining piles to be crossed, and the drilling depth is 2m larger than the bottom slab of the underground cavity area. The spacing between adjacent drilling holes is such that the space of the underground cavity area corresponding to the drilling range is completely filled with backfill soil. Drill holes at each pile location of the retaining wall piles to be penetrated and form each pile hole; Before the construction of cast-in-place piles in each pile hole, anti-lateral pressure steel casings are installed in the backfill soil on both sides of the corresponding pile hole, and the anti-lateral pressure steel casings are retrieved after the construction of the cast-in-place piles is completed.

2. The method for constructing retaining piles for traversing underground cavities as described in claim 1, characterized in that, When backfilling underground cavities, the skip-hole method is used for drilling.

3. The method for constructing retaining piles through underground cavities as described in claim 1, characterized in that, When backfilling underground cavities, first backfill the portion from the bottom slab to the opening of the cavity, and then backfill the portion from the top slab to the ground surface.

4. The method for constructing retaining piles through underground cavities as described in claim 3, characterized in that, When backfilling the area from the bottom slab to the opening of the underground cavity, plain soil is used for backfilling. During the backfilling process, rotary drilling is used for compaction, and water immersion deposition is used to increase the density of the backfill soil.

5. The method for constructing retaining piles through underground cavities as described in claim 1, characterized in that, At each pile location to be penetrated by the retaining wall piles, the skip-hole method is used to open holes and form each pile hole.

6. The method for constructing retaining piles through underground cavities as described in claim 1, characterized in that, The bottom of the anti-lateral pressure steel casing is at least 0.5m lower than the bottom plate of the underground cavity area, and the top of the anti-lateral pressure steel casing is at least 0.5m higher than the top plate of the underground cavity area.

7. The method for constructing retaining piles for traversing underground cavities as described in claim 1, characterized in that, When installing the anti-lateral pressure steel casing, the casing pile hole is first formed, and then the anti-lateral pressure steel casing is lowered; after the anti-lateral pressure steel casing is retrieved, the casing pile hole is backfilled.

8. The method for constructing retaining piles through underground cavities as described in claim 1, characterized in that, The diameter of the anti-lateral pressure steel casing is not less than the diameter of the corresponding pile hole.

Images