Underground pipeline laying structure suitable for high expansive soil area
By arranging sand cushions and water-isolating cushion structures around underground pipelines in high-expansive soil areas, the problem of pipeline damage due to deformation of expansive soils is solved, and the effect of reducing construction costs and engineering quantities is achieved.
Patent Information
- Application Number
- CN202421067946.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-16
- Publication Date
- 2025-01-24
- Estimated Expiration
- 2034-05-16
AI Technical Summary
In areas with high expansion soil, underground pipelines are easily deformed or damaged by the expansion and contraction of surrounding soils. The existing treatment methods are large and uneconomical.
The structure of the sand cushion layer and the water septum cushion layer is used around the pipeline. The sand cushion layer reduces the effects of the expansion soil on the pipeline.
Effectively reduce the squeezing force of the expansion soil on the pipeline, prevent the impact of leakage on the soil, and reduce the construction cost and engineering volume.
Smart Images
Figure CN222392123U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of underground pipeline design optimization in high-expansion soil areas, in particular to an underground pipeline laying structure suitable for high-expansion soil areas. Background Art
[0002] In areas with high expansion soil, underground pipelines are generally buried at a shallow depth. Since expansive soil has the characteristics of expanding when exposed to water and shrinking when losing water, the soil around the pipeline is easily affected by humidity changes such as atmospheric rainfall, causing expansion and contraction. In addition, underground pipelines themselves are water conveyance structures, and leakage is inevitable.
[0003] The soil around underground pipelines will expand when it encounters water, which will produce a large expansion force on the pipelines, causing the pipelines to bulge, deform, or even be squeezed and damaged. Once the pipeline is damaged, the water inside it will intensify the impact on the surrounding expansive soil, thereby intensifying the expansion and contraction effect, and will also have an adverse impact on surrounding structures.
[0004] Generally speaking, there are two ways to deal with pipelines in areas with high expansion soil. One is to replace the soil, that is, completely replace the original expansion soil; the other is to set the pipeline in a leak detection ditch (channel) or to install it overhead. No matter which method is used, the treatment workload is often large and uneconomical. Utility Model Content
[0005] The utility model aims to provide an underground pipeline laying structure suitable for high expansive soil areas, so as to solve the problems in the prior art that underground pipelines in expansive soil areas are deformed or even damaged by the surrounding expansive soil, and the existing treatment methods are large in engineering workload and uneconomical.
[0006] The utility model is realized by adopting the following technical solutions:
[0007] The utility model provides an underground pipeline laying structure suitable for areas with high expansive soil, comprising a pipeline arranged in a foundation pit, wherein sand cushion layers are arranged on both sides of the pipeline and at the bottom thereof, and the sand cushion layers are used to reduce the influence of the expansive soil on the pipeline; a load-bearing waterproof cushion layer is arranged around the sand cushion layer, and the load-bearing waterproof cushion layer is used to bear the pipeline and the sand cushion layer and to support the surrounding expansive soil, and to prevent water leakage from the pipeline into the surrounding expansive soil; an improved soil layer is laid above the load-bearing waterproof cushion layer.
[0008] As the preferred technical solution:
[0009] The load-bearing waterproof cushion layer forms a closed structure around the sand cushion layer.
[0010] As the preferred technical solution:
[0011] The inner side of the load-bearing waterproof cushion layer contacts the sand cushion layer, the outer bottom side of the load-bearing waterproof cushion layer contacts the bottom of the foundation pit, and the outer left and right sides of the load-bearing waterproof cushion layer contact the two side pit walls of the foundation pit.
[0012] As the preferred technical solution:
[0013] The load-bearing and waterproof cushion layer adopts a lime soil cushion layer.
[0014] As the preferred technical solution:
[0015] The improved soil layer is made of original soil with lime added.
[0016] As the preferred technical solution:
[0017] The improved soil layer is compacted layer by layer on the load-bearing waterproof cushion layer.
[0018] As the preferred technical solution:
[0019] The thickness of the improved soil layer is greater than 500 mm.
[0020] As the preferred technical solution:
[0021] The sand cushion layer is made of medium-coarse sand and gravel.
[0022] As the preferred technical solution:
[0023] The particle size of the medium-coarse sandstone is between 0.5 and 2 mm.
[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:
[0025] 1. The utility model arranges a sand cushion layer around the pipeline to form a deformation buffer zone, which effectively reduces the squeezing of the pipeline by the lateral expansion force, and arranges a gray soil cushion layer around the sand cushion layer to support the surrounding soil to meet the support bearing requirements. In addition, since the gray soil cushion layer has weak water permeability, a waterproof belt is formed around the outer side of the pipeline. When the pipeline leaks, the way for water to infiltrate into the original expansive soil is blocked, thereby eliminating the expansive soil effect of pipeline leakage.
[0026] 2. The underground pipeline laying structure suitable for high expansion soil areas of the utility model reduces the impact of high expansion soil on the pipeline, and the construction is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 The utility model is a schematic structural diagram of an underground pipeline laying structure suitable for high expansion soil areas.
[0028] Icon: 1-pipeline, 2-sand cushion, 3-bearing waterproof cushion, 4-improved soil layer. DETAILED DESCRIPTION
[0029] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0030] Example 1
[0031] like Figure 1 As shown, this embodiment proposes an underground pipeline laying structure suitable for high expansion soil areas, including a pipeline 1 arranged in a foundation pit, and sand cushion layers 2 are arranged on both sides and at the bottom of the pipeline 1. Since sand and gravel have the characteristic of large porosity, they are arranged in three directions where the pipeline 1 is affected by expansion deformation to form a deformation buffer zone, which can effectively reduce the squeezing effect of the lateral expansion force on the pipeline 1.
[0032] In this embodiment, the sand cushion layer 2 is made of medium-coarse sand and gravel, and the particle size of the medium-coarse sand and gravel is between 0.5-2 mm.
[0033] The sand cushion layer 2 is surrounded by a load-bearing waterproof cushion layer 3, which is used to bear the pipeline 1 and the sand cushion layer 2, support the surrounding expansive soil, and prevent the pipeline 1 from leaking into the surrounding expansive soil. The load-bearing waterproof cushion layer 3 forms a closed structure around the sand cushion layer 2 to improve the load-bearing effect. The inner side of the load-bearing waterproof cushion layer 3 is in close contact with the sand cushion layer 2, the outer bottom side of the load-bearing waterproof cushion layer 3 is in close contact with the bottom of the foundation pit, and the outer left and right sides of the load-bearing waterproof cushion layer 3 are in close contact with the pit walls on both sides of the foundation pit.
[0034] In this embodiment, the load-bearing waterproof cushion layer 3 is a lime soil cushion layer, which has high bearing capacity and weak water permeability, and can meet the bearing capacity requirements of the bearing layer of the general structure foundation. The lime soil cushion layer forms a waterproof belt around the outer side of the pipeline 1. When the pipeline 1 leaks, the lime soil cushion layer blocks the way for the water flow to penetrate into the original expansive soil, eliminating the expansive soil effect of the pipeline 1 leaking.
[0035] An improved soil layer 4 is arranged above the load-bearing waterproof cushion layer 3, and the improved soil layer 4 is compacted in layers on the load-bearing waterproof cushion layer 3. The improved soil layer 4 is made of original soil with a thickness of more than 500 mm and added with lime. Since expansive soil has thixotropy, that is, after the original soil is disturbed by excavation, the backfill soil has the characteristics of enhanced expansibility and reduced mechanical properties, the use of improved soil can effectively improve the soil properties.
[0036] The utility model arranges a sand cushion layer 2 around the pipeline 1 to form a deformation buffer zone, which effectively reduces the squeezing of the pipeline 1 by the lateral expansion force, and arranges a gray soil cushion layer around the sand cushion layer 2 to support the surrounding soil to meet the support bearing requirements. Moreover, since the gray soil cushion layer has weak water permeability, a waterproof belt is formed around the outer side of the pipeline 1. When the pipeline 1 leaks, the way for the water flow to infiltrate into the original expansive soil is cut off, thereby eliminating the expansive soil effect of the pipeline 1 leakage.
[0037] The underground pipeline laying structure suitable for high-expansion soil areas of the utility model reduces the influence of high-expansion soil on the pipeline, and the construction is simple and convenient with low cost.
[0038] Take the red clay soil in a certain area as an example. The expansion force of the expansive soil can reach up to 300kPa when it expands freely in water. The soil pressure at a height of 1m is about 19kPa. The expansion force of 300kPa is equivalent to the soil pressure at a depth of nearly 20m or the water pressure of 30m. The stress characteristics of general pipelines are that they can withstand internal pressure well, but their ability to withstand external pressure is weak. The external pressure that a conventional-sized pipeline can withstand generally does not exceed 5m of soil pressure. Such a huge expansion force acts on the outside of the pipeline body, and the pipeline will be squeezed and damaged. Whether it is replacing the expansive soil around the pipeline in the expansive soil area, setting the pipeline in the leak detection ditch (channel) or overhead, or re-customizing the pipeline and increasing the pipeline wall thickness, the cost is relatively high and uneconomical.
[0039] The structure of the utility model has low material price, simple structure and convenient construction, and can avoid damage to the pipeline caused by squeezing of expansion soil and greatly reduce the cost.
[0040] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. An underground pipeline laying structure suitable for high expansive soil areas, characterized by: It comprises a pipeline arranged in a foundation pit, wherein sand cushion layers are arranged on both sides of the pipeline and at the bottom thereof, and the sand cushion layers are used to reduce the influence of the expansive soil on the pipeline; a load-bearing waterproof cushion layer is arranged around the sand cushion layer, and the load-bearing waterproof cushion layer is used to bear the pipeline and the sand cushion layer and to support the surrounding expansive soil, and to prevent water leakage from the pipeline into the surrounding expansive soil; an improved soil layer is laid above the load-bearing waterproof cushion layer.
2. The underground pipeline laying structure suitable for high expansion soil areas according to claim 1 is characterized in that: The load-bearing waterproof cushion layer forms a closed structure around the sand cushion layer.
3. The underground pipeline laying structure suitable for high expansive soil areas according to claim 2 is characterized in that: The inner side of the load-bearing waterproof cushion layer contacts the sand cushion layer, the outer bottom side of the load-bearing waterproof cushion layer contacts the bottom of the foundation pit, and the outer left and right sides of the load-bearing waterproof cushion layer contact the two side pit walls of the foundation pit.
4. The underground pipeline laying structure suitable for high expansion soil areas according to claim 1 is characterized in that: The load-bearing and waterproof cushion layer adopts a lime soil cushion layer.
5. The underground pipeline laying structure suitable for high expansive soil areas according to claim 1 is characterized in that: The improved soil layer is compacted layer by layer on the load-bearing waterproof cushion layer.
6. The underground pipeline laying structure suitable for high expansive soil areas according to claim 1 is characterized in that: The thickness of the improved soil layer is greater than 500 mm.
7. The underground pipeline laying structure suitable for high expansive soil areas according to claim 1 is characterized in that: The sand cushion layer is made of medium-coarse sand and gravel.
8. The underground pipeline laying structure suitable for high expansion soil areas according to claim 7 is characterized in that: The particle size of the medium-coarse sandstone is between 0.5 and 2 mm.