Layered ramming and anti-seepage cushion structure for collapsible loess trench

Abstract

The utility model discloses a layered ramming and anti -infiltration cushion layer structure for collapsible loess pipe trench, it includes original collapsible loess layer, top ramming fixed raw soil layered ramming cushion layer, raw soil cushion layer top ramming fixed ash soil layered ramming cushion layer, ash soil cushion layer top pours fixed concrete cushion layer, concrete cushion layer top lays fixed professional anti -infiltration layer, professional anti -infiltration layer top places cushion block, and the rainwater pipeline is placed at the top of the cushion block, and the rubber ring is set in the head and tail connecting place of rainwater pipeline. The utility model discloses through ash soil cushion layer eliminates loess collapsibility, improves the strength of foundation, and concrete cushion layer protects professional anti -infiltration layer and realizes reliable vertical anti -infiltration, and concrete retaining wall and support block realize firm lateral support, and the structure systematicity has solved the problem that loess area pipe trench is easy to settle and seepage failure.

Description

Technical Field

[0001] This utility model relates to the field of pipe trench engineering technology, and in particular to a layered compaction and seepage prevention cushion structure for pipe trenches in collapsible loess. Background Technology

[0002] In municipal engineering or infrastructure construction, the laying of rainwater or sewage pipe trenches is a necessary step. When the trench project crosses collapsible loess areas, it faces severe geotechnical engineering challenges.

[0003] Collapsible loess is characterized by large pores and loose structure. Its most significant hazard is that when it is wetted by water, the soil structure will be rapidly destroyed, resulting in significant additional settlement, i.e., collapse. This collapse leads to a sharp decrease in the bearing capacity of the foundation, which can easily cause cracking, deformation or even collapse of the pipe trench structure, leading to pipe breakage or leakage.

[0004] While existing trench treatment technologies may employ methods such as replacement or compaction to treat the foundation, they often focus only on physical compaction and fail to fundamentally eliminate the collapsibility of loess. Furthermore, conventional anti-seepage layers often have a simple structure and lack systematic blocking of vertical and lateral seepage. In addition, the anti-seepage layer itself is easily punctured by hard particles during construction or subsequent settlement, leading to the failure of the anti-seepage barrier. Once water intrudes, it will still come into contact with the collapsible loess below, ultimately causing the entire trench structure to fail.

[0005] Therefore, this utility model proposes a layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess to overcome the shortcomings of the prior art. Utility Model Content

[0006] In view of the problems existing in the technology of pipe trenches for collapsible loess, such as failure to fundamentally eliminate the collapsibility of loess, lack of systematic blocking of vertical and lateral seepage, and easy puncture of the seepage barrier layer leading to functional failure, this utility model aims to provide a layered compaction and seepage barrier layer structure for pipe trenches for collapsible loess with improved structure that can effectively solve the above problems.

[0007] This utility model provides a layered compaction and seepage prevention cushion structure for pipe trenches in collapsible loess, comprising: an original collapsible loess layer, and a layered compacted cushion layer of plain soil that is compacted and fixed on top of the original collapsible loess layer.

[0008] The top of the compacted subgrade is compacted and fixed with a layer of compacted lime-soil, the top of the compacted lime-soil layer is poured and fixed with a concrete layer, and the top of the concrete layer is laid and fixed with a professional anti-seepage layer.

[0009] A pad is placed on top of the professional waterproof layer, and a rainwater pipe is placed on top of the pad. Rubber rings are fitted at the ends of the rainwater pipe.

[0010] The top of the professional seepage-proof layer and the surrounding area of ​​the rainwater pipe are backfilled and compacted.

[0011] A concrete retaining wall was integrally cast on both sides of the original collapsible loess layer and the backfilled and compacted layer, and a support block was fixedly connected to the outer wall of the concrete retaining wall.

[0012] Preferably, the subgrade compacted layer consists of three sub-layers of subgrade compacted layer by layer from bottom to top. This multi-layer, sequential construction method ensures the overall density and uniformity of the subgrade compacted layer, providing a stable foundation for the superstructure.

[0013] Preferably, the lime-soil layered compacted cushion layer includes three layers of lime-soil sub-layers that are compacted layer by layer from bottom to top. By compacting layer by layer, the lime and loess are ensured to react fully and be compacted, so as to fundamentally eliminate the collapsibility of loess and improve the water stability of the foundation.

[0014] Preferably, the backfill compaction layer includes five backfill sub-layers that are compacted layer by layer from bottom to top. The layered backfill compaction method helps to protect the rainwater pipes below from the impact damage of a single large-depth backfill and ensures the uniform compaction of the backfill soil.

[0015] Preferably, the rainwater pipe includes multiple pipe sections connected end to end, and the diameter of the inlet end of each pipe section is smaller than the diameter of its outlet end. This structural design, with the inlet diameter smaller than the outlet diameter, is conducive to the smooth flow of water and reduces water resistance.

[0016] Preferably, in a rainwater pipe consisting of multiple pipe segments connected end to end, a rubber ring is annularly placed at the junction of the pipe segments and fills the gaps between the pipe segments with its own elasticity to achieve a reliable seal and prevent water leakage inside the pipe from adversely affecting the foundation.

[0017] Preferably, the total backfill thickness is greater than the outer diameter of the rainwater pipe, based on the backfill compaction layer consisting of five layers of backfill sub-layers compacted from bottom to top, to ensure that the rainwater pipe is completely covered and is in the compacted soil layer, providing it with sufficient overlay protection.

[0018] Preferably, the top surface of the concrete retaining wall is level with the top surface of the backfill compaction layer to form a complete lateral protection structure; and the support blocks are arranged in an array at intervals on the outer side wall of the concrete retaining wall to provide a stable lateral support force for the concrete retaining wall and prevent it from overturning or deforming under the action of the outer soil pressure.

[0019] This utility model has the following beneficial effects: 1. This utility model solves the problems of low bearing capacity, high porosity, and uneven settlement when exposed to water in the existing technology of collapsible loess foundation by setting up a layered compacted subgrade and a layered compacted lime-soil subgrade. It achieves the effect of eliminating the collapsibility of loess and improving the foundation strength and water stability through physical compaction and chemical modification.

[0020] 2. This utility model solves the problems in the prior art where the seepage prevention layer is easily punctured by hard particles in the lower layer, leading to seepage prevention failure, or the seepage prevention effect is poor due to uneven base surface, by setting a concrete cushion layer and a professional seepage prevention layer on top of the compacted lime-soil cushion layer in sequence. It achieves the effect of the concrete cushion layer providing a flat and solid protective base surface for the professional seepage prevention layer, and the combination of the two reliably blocking vertical water seepage.

[0021] 3. This utility model solves the problems of lack of lateral protection and easy water seepage from the edge of the trench in the prior art by integrally casting concrete retaining walls on both sides of the trench structure and fixing support blocks to the outside of the retaining walls. It achieves the effect of forming a three-dimensional anti-seepage system in conjunction with a professional anti-seepage layer, and the support blocks can ensure that the retaining wall can resist lateral soil pressure for a long time. Attached Figure Description

[0022] Figure 1 This is a front perspective view of a layered compaction and seepage-proof cushion layer structure for a pipe trench in collapsible loess, as proposed in this utility model. Figure 2 This is a partial structural breakdown diagram of a layered compaction and seepage prevention cushion layer backfill compaction layer for a pipe trench in collapsible loess, as proposed in this utility model. Figure 3 This is a partial structural cross-sectional view of a layered compaction and seepage prevention cushion layer for a pipe trench in collapsible loess, as proposed in this utility model. Figure 4 This is a partial structural diagram of a layered compaction and seepage prevention cushion layer for a pipe trench in collapsible loess, as proposed in this utility model.

[0023] Legend: 1. Original collapsible loess layer; 2. Plain soil layered compacted cushion layer; 3. Lime soil layered compacted cushion layer; 4. Concrete cushion layer; 5. Professional seepage prevention layer; 6. Backfill compacted layer; 7. Pad blocks; 8. Rainwater pipes; 9. Rubber rings; 10. Concrete retaining wall; 11. Support blocks. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Example

[0025] Please refer to Figures 1 to 4 This utility model provides a layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess, which aims to solve the problems in the existing technology of pipe trench structures in collapsible loess that are prone to uneven settlement due to the loess collapsing when it gets wet, and the lack of a systematic seepage-proof structure.

[0026] like Figures 1 to 4 As shown, the layered compaction and seepage-proof cushion structure for the pipe trench in collapsible loess includes an original collapsible loess layer 1, which serves as the base bearing layer of the entire pipe trench structure. A layered compacted plain soil cushion layer 2 is compacted and fixed on top of the original collapsible loess layer 1. The plain soil cushion layer 2 is used to initially reduce the porosity of the original loess and enhance the integrity and bearing capacity of the base. A layered compacted lime-soil cushion layer 3, serving as the core compacted reinforcement layer, is compacted and fixed on top of the plain soil cushion layer 2. The lime-soil cushion layer 3 is used to improve the soil strength and eliminate the collapsibility of the loess. A concrete cushion layer 4 is poured and fixed on top of the lime-soil cushion layer 3. The concrete cushion layer 4 is used to prevent the sharp particles of the lower lime-soil cushion layer from damaging the upper structure and to provide a flat and solid construction base for the waterproof layer. A professional anti-seepage layer 5 is laid and fixed on top of the trench. The professional anti-seepage layer 5 is used to prevent surface water and groundwater from entering the trench. Multiple pads 7 are placed on top of the professional anti-seepage layer 5. Rainwater pipes 8 are placed on top of the pads 7. Rubber rings 9 are fitted at the ends of the rainwater pipes 8. The rubber rings 9 are used to seal gaps and prevent pipe leakage. A backfill compaction layer 6 is backfilled on top of the professional anti-seepage layer 5 and around the rainwater pipes 8. The backfill compaction layer 6 completely covers the rainwater pipes 8. Concrete retaining walls 10 of the same height are integrally cast on both sides of the original collapsible loess layer 1 to the backfill compaction layer 6. The concrete retaining walls 10 are used to prevent edge seepage. Multiple support blocks 11 are fixedly connected to the outer walls of the two concrete retaining walls 10. The support blocks 11 are used to support the concrete retaining walls 10.

[0027] like Figure 4 As shown, the subgrade compacted layer 2 consists of three subgrade layers of subgrade compacted layer by layer from bottom to top. like Figure 3As shown, on top of the compacted subgrade 2, the compacted lime-soil subgrade 3 consists of three layers of lime-soil sub-layers compacted from bottom to top; a concrete subgrade 4 is poured and fixed flat on top of the compacted lime-soil subgrade 3; a professional anti-seepage layer 5 is laid and fixed on top of the concrete subgrade 4; this structural combination utilizes the compacted lime-soil subgrade 3 to eliminate the collapsibility of loess, utilizes the concrete subgrade 4 to provide a solid and flat base for the professional anti-seepage layer 5 and prevents it from being punctured by lime-soil particles, and utilizes the professional anti-seepage layer 5 to achieve vertical anti-seepage of the main body.

[0028] The lime-soil layer 3 uses a volume ratio of lime to loess of 3:7. Each layer is loosely laid 250 mm and compacted to 150 mm. The compaction coefficient is ≥0.95. After curing for 7 days, the measured collapsibility coefficient δs is ≤0.010 (GB 50025-2018), indicating that the collapsibility has been eliminated.

[0029] The professional seepage prevention layer 5 is a 1.5mm thick HDPE geomembrane with a tensile strength ≥25kN / m, an overlap width of 100mm, and double-track hot-melt welds. It can be inflated to 0.2 MPa and held under pressure for 5 minutes without leakage. 300 g / m² non-woven geotextile is laid on both the top and bottom of the membrane for protection / filtration.

[0030] Please refer to Figure 1 To achieve lateral seepage prevention, a concrete retaining wall 10 is integrally cast on both sides of the original collapsible loess layer 1, the plain soil layer 2, the lime-soil layer 3, the concrete cushion layer 4, the professional seepage prevention layer 5, and the backfill compacted layer 6. The top surface of the concrete retaining wall 10 is level with the top surface of the backfill compacted layer 6. To enhance the stability of the concrete retaining wall 10, support blocks 11 are fixedly connected to the outer wall of the concrete retaining wall 10. The support blocks 11 are arranged in an array at intervals on the outer wall of the concrete retaining wall 10.

[0031] Ø12 steel bar short sections are pre-embedded at every 2m height on the outer side of the concrete retaining wall 10, with an exposed length of 150mm; the support block 11 is a C25 precast concrete block with dimensions of 400mm×400mm×200mm, and Ø14 sleeves are left at the corresponding positions. During installation, the steel bar short sections are inserted and filled with C30 micro-expansion mortar to form a fixed connection.

[0032] As a preferred embodiment, please refer to Figure 4 In order to initially compact the foundation, the subgrade layer 2 consists of three subgrade layers of subgrade compacted layer by layer from bottom to top.

[0033] As a preferred embodiment, please refer to Figure 3 In order to reinforce the core and eliminate collapsibility, the lime-soil layer 3 consists of three layers of lime-soil sub-layers that are compacted layer by layer from bottom to top.

[0034] As a preferred embodiment, please refer to Figure 2 In order to protect the rainwater pipe 8, the backfill compaction layer 6 consists of five backfill sub-layers that are compacted layer by layer from bottom to top.

[0035] In a preferred embodiment, the total backfill thickness of the backfill compaction layer 6 is greater than the outer diameter of the rainwater pipe 8, based on the five backfill sub-layers that are compacted layer by layer from bottom to top in the backfill compaction layer 6, in order to ensure that the rainwater pipe 8 is completely covered.

[0036] As a preferred embodiment, please refer to Figure 1 The rainwater pipe 8 consists of multiple pipe sections connected end to end, and the diameter of the inlet end of each pipe section is smaller than the diameter of its outlet end. This structure of small inlet and large outlet (socket joint) is conducive to the smooth flow of water.

[0037] As a preferred embodiment, the rainwater pipe 8 is a socket-type reinforced concrete pipe with the inner diameter of the socket being 8 mm larger than the outer diameter of the spigot, and the socket depth being 100 mm; the rubber ring 9 is a Ø40 mm hollow neoprene rubber ring, which is installed in the groove of the socket and has a compression rate of 35% after the spigot is pushed in, thus achieving a seal.

[0038] As a preferred embodiment, please refer to Figure 1 To ensure the integrity and stability of lateral protection, the top surface of the concrete retaining wall 10 is level with the top surface of the backfill compacted layer 6; and the support blocks 11 are arranged in an array at intervals on the outer side wall of the concrete retaining wall 10 to provide stable lateral support for the concrete retaining wall 10.

[0039] Working principle: First, the original collapsible loess layer 1 serves as the base. The above-ground plain soil compaction layer 2 consists of three layers of plain soil sub-layers that are compacted layer by layer from bottom to top to initially compact the base and improve the overall bearing capacity. The key is the lime-soil compaction layer 3, which consists of three layers of lime-soil sub-layers that are compacted layer by layer from bottom to top. Through the chemical reaction between lime and loess, the engineering properties of the soil are changed, fundamentally eliminating the collapsibility of loess and constructing a solid and highly water-stable core bearing platform. In terms of seepage prevention, the structure has constructed a three-dimensional seepage prevention system; the professional seepage prevention layer 5, as the main vertical seepage prevention barrier, is laid on the concrete cushion layer 4. The function of the concrete cushion layer 4 is to provide a flat and solid construction base for the professional seepage prevention layer 5 and to prevent it from being punctured by hard particles in the lower layer of lime-soil compacted cushion layer 3, thus ensuring the long-term reliability of vertical seepage prevention. In terms of lateral protection, the integrally cast concrete retaining wall 10 forms a vertical water-blocking curtain on both sides of the structure, which effectively prevents water from seeping in from the side edge of the trench. The support blocks 11 are arranged in an array at intervals on the outer wall of the concrete retaining wall 10, providing stable lateral support for the concrete retaining wall 10 and preventing deformation and failure under the outer soil pressure. In terms of pipe support and internal protection, the pad block 7 stably supports the rainwater pipe 8 on the professional anti-seepage layer 5. The rubber ring 9 at the joint of the rainwater pipe 8 is set in a ring and fills the gap between the pipe sections to prevent leakage of the pipe joints. The backfill compaction layer 6 includes five layers of backfill sub-layers that are compacted layer by layer from bottom to top to completely cover and compact the rainwater pipe 8. The collapsibility of the pad layer 3 is eliminated by the layered compaction of lime and soil. Combined with the three-dimensional anti-seepage system of the professional anti-seepage layer 5 and the concrete retaining wall 10, the structure systematically isolates the contact between water and the underlying original collapsible loess layer 1, and solves the technical problem of structural instability caused by uneven settlement and water seepage in the collapsible loess trench.

Claims

1. A layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess, comprising: Original collapsible loess layer (1), and compacted plain soil layer (2) that is compacted and fixed on top of the original collapsible loess layer (1). Its features are, The top of the compacted subgrade (2) is compacted and fixed with a layer of compacted lime-soil (3), the top of the compacted lime-soil (3) is poured and fixed with a concrete cushion (4), and the top of the concrete cushion (4) is laid and fixed with a professional anti-seepage layer (5). A pad (7) is placed on top of the professional seepage-proof layer (5), and a rainwater pipe (8) is placed on top of the pad (7). A rubber ring (9) is fitted at the connection of the beginning and end of the rainwater pipe (8). The top of the professional seepage-proof layer (5) and the periphery of the rainwater pipe (8) are backfilled with a backfill compaction layer (6). A concrete retaining wall (10) is integrally cast on both sides of the original collapsible loess layer (1) to the backfilled and compacted layer (6), and a support block (11) is fixedly connected to the outer wall of the concrete retaining wall (10).

2. The layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess according to claim 1, characterized in that, The subgrade compacted cushion layer (2) includes three subgrade layers of subgrade compacted layer by layer from bottom to top.

3. The layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess according to claim 1, characterized in that, The rammed sub-base (3) consists of three layers of rammed sub-bases that are rammed from bottom to top.

4. The layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess according to claim 1, characterized in that, The backfill compaction layer (6) includes five backfill sub-layers that are compacted layer by layer from bottom to top. Each layer is loosely laid for 300mm and compacted to 200mm, with a compaction coefficient ≥0.

92.

5. The layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess according to claim 1, characterized in that, The rainwater pipe (8) includes multiple pipe sections connected end to end, and the diameter of the inlet end of each pipe section is smaller than the diameter of its outlet end.

6. The layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess according to claim 5, characterized in that, The rubber ring (9) is arranged in a ring shape at the junction of the beginning and end of the pipe section and fills the gap between the pipe sections.

7. The layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess according to claim 4, characterized in that, The total backfill thickness of the backfill compaction layer (6) is greater than the outer diameter of the rainwater pipe (8).

8. The layered compaction and seepage-proof cushion layer structure for pipe trenches in collapsible loess according to claim 1, characterized in that, The top surface height of the concrete retaining wall (10) is the same as the top surface height of the backfill compacted layer (6), and the support blocks (11) are arranged in an array at intervals on the outer side wall of the concrete retaining wall (10).

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