Loess slope sinkhole treatment method

Abstract

The invention discloses a loess slope sinkhole treatment method which comprises the following steps: S1, checking a sinkhole formed on a loess slope, and finding out the forming type of the sinkhole; s2, according to the formation type of the sinkhole, a corresponding loess slope water interception and drainage treatment scheme is constructed; s3, a sinkhole formed in the loess slope is blocked; s4, according to the loess slope water interception and drainage treatment scheme, corresponding water interception and drainage ditches are built; s5, a reservoir used for collecting drained water is dug at the slope toe of the loess slope, herbaceous plants are planted on the loess slope, and the loess slope is irrigated through the reservoir; according to the scheme, the stability of the side slope is improved by slowing down the development of the sinkhole in the surface of the loess side slope, meanwhile, the mutual relation between the slope body and the sinkhole is comprehensively considered, a corresponding water interception and drainage treatment scheme is provided for the problem that the loess side slope is unstable due to different causes and sinkholes in different positions, and the stability of the side slope is improved. Therefore, the treatment effect on the loess slope sinkhole is improved.

Description

Technical Field

[0001] The invention relates to the technical field of slope management, and in particular to a method for managing sinkholes on a loess slope. Background Art

[0002] Loess, as a loose sediment formed in the Quaternary period, is widely distributed in Qinghai, Gansu and other places in my country. Its special deposition and development environment has created a series of geological characteristics. In terms of landform, it manifests itself as unique loess ridges, loess hills and loess discs, which make loess highly collapsible, with developed vertical joints, relatively large pores, disintegration and strong structure. Due to these characteristics of loess, geological disasters such as landslides, collapses, ground fissures and ground collapses occur frequently in loess areas. Therefore, water, as an external condition, has an extremely important influence on loess slopes.

[0003] At present, the existing drainage measures and related human engineering activities in the loess region have achieved a certain degree of stabilization of the loess slopes. However, for some special loess slopes, it will have the opposite effect and aggravate the deformation of the slopes; such as loess slopes with developed sinkholes. As a unique geological phenomenon in the loess region, the development of loess sinkholes has aggravated serious soil erosion and has become a triggering factor of the above-mentioned geological disasters to a certain extent.

[0004] In the formation process of sinkholes, the unique stratum lithology and topography of the loess area are the fundamental factors for the development of sinkholes, and the arid and semi-arid climate conditions and human activities are the triggering conditions for the development of sinkholes. Among them, water contributes the most to the development of sinkholes, and the action mode of water is different in different stages. The existence of water causes loess to undergo collapsing, erosion, and subsidence. The formation mechanism of sinkholes is a complex physical and chemical process. At different locations on the slope, the formation mechanism of sinkholes varies greatly due to different development conditions and stages. It can be divided into three formation mechanisms: collapsing-subsidence-erosion type, erosion-wet collapse-subsidence type, and subsidence-wet collapse-erosion type. The main body of loess sinkholes is hidden in the soil, and the depth and position often change greatly with the advancement of time. In addition, the causes of loess sinkholes are complex and are greatly affected by regional topography, stratum lithology, etc., and the impact on loess slopes is diverse. Therefore, the study of the prevention and control of sinkholes on loess slopes is relatively complex, and has certain practical significance for disaster prevention and mitigation. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for treating sinkholes in loess slopes to solve the problems mentioned in the above-mentioned background technology.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: A method for treating a sinkhole in a loess slope is provided, which comprises the following steps: S1: Investigate the sinkholes that have formed on the loess slope and find out the types of sinkholes; S2: According to the formation type of sinkholes, construct the corresponding loess slope interception and drainage treatment plan; S3: Block the sinkholes formed on the loess slope; S4: Build corresponding interception and drainage ditches according to the interception and drainage treatment plan for loess slopes; S5: Dig a reservoir for collecting drainage at the foot of the loess slope, plant herbaceous plants on the loess slope, and use the reservoir for irrigation.

[0007] Furthermore, step S1 specifically includes: S11: Establish a high-precision three-dimensional model of the loess slope through drone photography; S12: For the fuzzy areas in the 3D model, conduct a targeted secondary human survey and fill in the missing sinkholes; S13: Physical detection of sinkholes hidden underground in loess slopes; S14: Combine steps S11-S13 to establish a corresponding record of loess slope sinkholes.

[0008] Furthermore, the types of sinkholes formed in step S2 include sinkholes of collapsing-undercutting-erosion type, sinkholes of erosion-collapsing-undercutting type, and sinkholes of erosion-collapsing-erosion type; Step S4 specifically includes: S41: if the sinkhole is a sinkhole of the collapsible-undercutting-erosion type, execute step S42; if the sinkhole is a sinkhole of the erosion-collapse-undercutting type, execute step S43; if the sinkhole is a sinkhole of the erosion-collapse-erosion type, execute step S44; S42: Build a drainage ditch at the top of the loess slope to connect all low-lying areas on the top of the slope, and lead several sections of drainage channels in the extension direction of the drainage ditch, and the drainage channels are arranged longitudinally along the valley of the loess slope; S43: Build a drainage ditch on the gentle slope near the boundary line between the steep and gentle loess slopes; and perform anti-seepage and soil consolidation treatment on the gentle slope between the drainage ditch and the boundary line between the steep and gentle slopes; S44: Spray slurry on the top surface of the slope, then lay a clay layer and plant vegetation that can effectively reduce infiltration.

[0009] Furthermore, the drainage ditch and intercepting ditch are uniformly built with mortar-laid stone flags in a trapezoidal shape, and a number of expansion joints are arranged at intervals in the extension direction of the drainage ditch and the intercepting ditch. The spacing of the expansion joints is 15-20m, and the width of the joint is 2cm. A drainage channel is arranged every 5-10m in the extension direction of the intercepting ditch.

[0010] Furthermore, the method for anti-seepage soil consolidation treatment in step S43 is: S431: Clear the debris on the gentle slope between the intercepting ditch and the boundary between the steep and gentle slopes, compact the gentle slope, and backfill and tamp the low-lying areas on the gentle slope to make it smooth; S432: Organic plastic film is laid on the gentle slope between the intercepting ditch and the steep-gentle boundary line; S433: Spray the slurry on the surface of the organic plastic film and ensure that the gentle slope has an inclination of 1-2°.

[0011] Furthermore, the method for sealing the sinkhole in step S3 is: first, the accumulated water infiltrated in the sinkhole is sucked out by a siphon method, and then the sinkhole is sealed and compacted with the original soil in the surrounding area.

[0012] Furthermore, when sealing the sinkholes, for the clustered sinkholes on the top of the slope close to the intercepting drainage ditch, the cracks and holes in the sinkholes are filled by spraying slurry, and then the sinkholes are grouted and masonry is performed according to the design requirements to form a permeable layer, and drainage holes connected to the permeable layer are opened on both sides of the intercepting drainage ditch.

[0013] Furthermore, when sealing the sinkholes, for the longitudinally connected sinkholes on the loess slope, the sinkholes are transformed into drainage channels by grouting and stone masonry.

[0014] The beneficial effects of the present invention are: 1. This plan aims to improve the stability of the slope by slowing down the development of sinkholes on the surface of the loess slope. At the same time, this plan comprehensively considers the relationship between the slope and the sinkholes, and provides corresponding interception and drainage treatment plans for the instability of the loess slope caused by sinkholes of different causes and in different locations, thereby improving the treatment effect of sinkholes on the loess slope.

[0015] 2. This scheme can use the existing sinkholes to construct a permeable layer and drainage channels, and cooperate with the constructed intercepting drainage ditches to enhance the water collection and drainage capacity of the intercepting drainage ditches, while reducing the excavation of the slope and reducing the difficulty of construction.

[0016] 3. This plan slows down the development of sinkholes on loess slopes through drainage management, while collecting drainage and using it for irrigation. This combination of drainage management and environmental restoration has achieved a virtuous cycle effect in the management of sinkholes on loess slopes, and is in line with the development concept of energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the drainage ditch structure. DETAILED DESCRIPTION

[0018] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0019] like Figure 1 As shown, the loess slope sinkhole treatment method of this scheme includes the following steps: S1: Investigate the sinkholes that have formed on the loess slopes and find out the types of sinkholes; specifically include: S11: Through drone photography, a high-precision three-dimensional model of the loess slope is established. The establishment of the three-dimensional model is of great significance for the location and arrangement of the sinkholes on the loess slope, and the drainage scheme layout can be set intuitively; S12: For the fuzzy areas in the 3D model, conduct a targeted secondary human survey and fill in the missing sinkholes; S13: Physical detection of sinkholes hidden underground in loess slopes; specifically, this scheme can use resistivity imaging technology and high-density electrical instrument for physical detection. Resistivity imaging technology measures the resistivity of underground media and obtains a two-dimensional profile image of its underground distribution to analyze the underground characteristics of landslides; this technology can provide two-dimensional or three-dimensional images of resistivity distribution in strata, and through analysis and interpretation of inversion images, identify changes in water content, and then infer groundwater levels and groundwater movement directions; according to the distribution law of high resistivity abnormal areas, underground cracks or developed cavities can be detected; high-density electrical instrument is an instrument used to detect the geoelectric characteristics of typical sections in landslide areas; it obtains a variety of geoelectric information by arranging electrodes and performing detection in a variety of electrode arrangements; this technology has the characteristics of both cross-section method and depth sounding method, and can divide strata through detection, discover hidden cracks, fault structures, and cavity development; S14: Combine steps S11-S13 to establish a corresponding record of loess slope sinkholes.

[0020] S2: According to the formation type of sinkholes, construct the corresponding loess slope interception and drainage treatment plan; the formation types of sinkholes include collapsible-underwater-erosion type sinkholes, erosion-collapse-underwater type sinkholes and erosion-collapse-erosion type sinkholes.

[0021] Among them, the formation location of the sinkhole of the collapsing-undercutting-erosion type is often located at the top of the slope. This is because the erosion of water flow is weaker in places with gentle slopes, and the collapsing effect of loess is the primary factor in the development of sinkholes. The general process is that after rainfall, rainwater gathers, and then the water gathered in the depression causes undercutting to carry away the loess particles, causing the collapsing to increase and gradually deepen, forming a height difference, thereby generating erosion to form a larger loess sinkhole. The formation location of the erosion-wet-collapse-undercutting type sinkhole is the intersection of steep and gentle terrain, often located in the middle of the slope. The water flow has a large gravitational potential energy at the beginning. When the gravitational potential energy is converted into kinetic energy, it has a strong scouring effect on the stratum, thus forming a depression that is convenient for water collection. The confluence of water flow increases the deadweight of the soil, and the wetting effect occurs, which deepens the development depth of the sinkhole. When it develops to a certain depth, the wetting effect weakens, the wetting effect of the water convergence becomes increasingly obvious, and the depth of the sinkhole is further deepened. The formation process of the subsidence-wetting-erosion type sinkhole is that water flows infiltrate along the joints and fissures, mainly in the top area of ​​the slope, taking away the loose fine particles in the soil, making the fissures interconnected, forming a concentrated infiltration channel; the soil collapses and deforms under the action of gravity, forming a depression that is convenient for water collection, and the sinkhole is initially formed; due to the existence of height difference, the erosion effect is obvious, and the sinkhole gradually expands. The formation of this type of sinkhole is mainly related to the surface water flow formed by rainfall.

[0022] S3: Seal the sinkholes that have formed on the loess slopes. The existence of sinkholes increases the infiltration depth and amount of rainfall on the loess slopes, destroys the stress balance in the slope, and reduces the stability of the loess slopes. The sealing of sinkholes is particularly important for loess. In the specific implementation, the siphon method is first used to suck out the accumulated water in the sinkholes, and then the original soil in the surrounding area is used to seal the sinkholes and compact them. S4: According to the interception and drainage treatment plan for loess slopes, build corresponding interception and drainage ditches; specifically include: S41: if the sinkhole is a sinkhole of the collapsible-underwater-erosion type, execute step S42; if the sinkhole is a sinkhole of the erosion-collapse-underwater type, execute step S43; if the sinkhole is a sinkhole of the erosion-collapse-underwater type, execute step S44; S42: Build a drainage ditch at the top of the loess slope to connect all low-lying areas on the top of the slope, and lead several sections of drainage channels in the extension direction of the drainage ditch, and the drainage channels are arranged longitudinally along the valley of the loess slope; S43: Build a drainage ditch on the gentle slope near the boundary line between the steep and gentle loess slopes; and carry out anti-seepage soil consolidation treatment on the gentle slope between the drainage ditch and the boundary line between the steep and gentle loess slopes; the method is: S431: Clear the debris on the gentle slope between the intercepting ditch and the boundary between the steep and gentle slopes, compact the gentle slope, and backfill and tamp the low-lying areas on the gentle slope to make it smooth; S432: Organic plastic film is laid on the gentle slope between the intercepting ditch and the steep-gentle boundary line; S433: Spray the slurry on the surface of the organic plastic film and ensure that the gentle slope has an inclination of 1-2°.

[0023] S44: Spray slurry on the top surface of the slope, then lay a clay layer and plant vegetation that can effectively reduce infiltration.

[0024] S5: Dig a reservoir for collecting drainage at the foot of the loess slope, plant herbaceous plants on the loess slope, and use the reservoir for irrigation.

[0025] The depth of the drainage ditch and intercepting ditch in this scheme is 0.8m, and they are uniformly built into a trapezoidal shape with mortar-laid stone slabs of MU30 strength, about 20cm thick, and the stone diameter is greater than 15cm. The ditch wall and ditch bottom are built with M7.5 mortar, and the ditch wall is outlined with M10 cement mortar. Several deformation joints are arranged at intervals in the extension direction of the drainage ditch and the intercepting ditch. The spacing of the deformation joints is 15-20m, and the width of the joint is 2cm. A drainage channel is arranged every 5-10m in the extension direction of the intercepting ditch.

[0026] As an optional implementation method, according to the field survey on the distribution of sinkholes on the existing loess slopes, it can be found that the number of sinkholes is the largest at the top of the slope, and on the surface of the loess slope, the slope is gentle and there are fewer sinkholes; there are often clusters of sinkholes at the top of the slope; therefore, when sealing the sinkholes, for the clustered sinkholes on the top of the slope close to the intercepting drainage ditch, the cracks and holes in the sinkholes are filled by spraying slurry, and then the sinkholes are grouted and masonry is carried out according to the design requirements to form a permeable layer, and drainage holes connected to the permeable layer are opened on both sides of the intercepting drainage ditch; for the longitudinally connected sinkholes on the loess slope, the sinkholes are transformed into drainage channels by grouting and masonry; this scheme uses the existing sinkholes to construct a permeable layer and drainage channels, and cooperates with the constructed intercepting drainage ditch, thereby enhancing the water collection and drainage capacity of the intercepting drainage ditch while reducing the excavation of the slope and reducing the difficulty of construction.

[0027] In summary, this scheme improves the stability of the slope by slowing down the development of sinkholes on the surface of the loess slope. At the same time, this scheme comprehensively considers the relationship between the slope and the sinkholes, and provides corresponding interception and drainage treatment plans for the instability of the loess slope caused by sinkholes of different causes and in different locations, thereby improving the treatment effect of the sinkholes on the loess slope; in addition, this scheme also collects drainage and uses it for irrigation. This combination of drainage treatment and environmental restoration has achieved a virtuous cycle effect for the treatment of sinkholes on the loess slope, which is in line with the development concept of energy conservation and emission reduction.

Claims

1. A method for treating a sinkhole on a loess slope, characterized in that: The following steps are involved: S1: Investigate the sinkholes that have formed on the loess slope and find out the types of sinkholes; S2: According to the formation type of sinkholes, construct the corresponding loess slope interception and drainage treatment plan; S3: Block the sinkholes formed on the loess slope; S4: Build corresponding interception and drainage ditches according to the interception and drainage treatment plan for loess slopes; S5: Dig a reservoir for collecting drainage at the foot of the loess slope, plant herbaceous plants on the loess slope, and use the reservoir for irrigation.

2. The method for treating sinkholes in loess slopes according to claim 1, characterized in that: Step S1 specifically includes: S11: Establish a high-precision three-dimensional model of the loess slope through drone photography; S12: For the fuzzy areas in the 3D model, conduct a targeted secondary human survey and fill in the missing sinkholes; S13: Physical detection of sinkholes hidden underground in loess slopes; S14: Combine steps S11-S13 to establish a corresponding record of loess slope sinkholes.

3. The method for treating sinkholes in loess slopes according to claim 1, characterized in that: The types of sinkholes formed in step S2 include sinkholes of collapsing-undercutting-erosion type, sinkholes of erosion-collapsing-undercutting type and sinkholes of erosion-collapsing-erosion type; Step S4 specifically includes: S41: if the sinkhole is a sinkhole of the collapsible-undercutting-erosion type, execute step S42; if the sinkhole is a sinkhole of the erosion-collapse-undercutting type, execute step S43; if the sinkhole is a sinkhole of the erosion-collapse-erosion type, execute step S44; S42: Build a drainage ditch at the top of the loess slope to connect all low-lying areas on the top of the slope, and lead several sections of drainage channels in the extension direction of the drainage ditch, and the drainage channels are arranged longitudinally along the valley of the loess slope; S43: Build a drainage ditch on the gentle slope near the boundary line between the steep and gentle loess slopes; and perform anti-seepage and soil consolidation treatment on the gentle slope between the drainage ditch and the boundary line between the steep and gentle slopes; S44: Spray slurry on the top surface of the slope, then lay a clay layer and plant vegetation that can effectively reduce infiltration.

4. The method for treating sinkholes in loess slopes according to claim 3 is characterized in that: The drainage ditch and intercepting ditch are uniformly built in a trapezoidal shape with mortar-laid stone slabs. A plurality of deformation joints are arranged at intervals in the extension direction of the drainage ditch and the intercepting ditch. The spacing of the deformation joints is 15-20m, and the width of the joint is 2cm. The drainage channel is arranged every 5-10m in the extension direction of the intercepting ditch.

5. The method for treating sinkholes in loess slopes according to claim 3 is characterized in that: The method for anti-seepage soil consolidation treatment in step S43 is: S431: Clear the debris on the gentle slope between the intercepting ditch and the boundary between the steep and gentle slopes, compact the gentle slope, and backfill and tamp the low-lying areas on the gentle slope to make it smooth; S432: Organic plastic film is laid on the gentle slope between the intercepting ditch and the steep-gentle boundary line; S433: Spray the slurry on the surface of the organic plastic film and ensure that the gentle slope has an inclination of 1-2°.

6. The method for treating sinkholes in loess slopes according to claim 3, characterized in that: The method for sealing the sinkhole in step S3 is: first, the accumulated water infiltrated in the sinkhole is sucked out by a siphon method, and then the sinkhole is sealed and compacted with the original soil in the surrounding area.

7. The method for treating sinkholes in loess slopes according to claim 6, characterized in that: When sealing the sinkholes, for the clustered sinkholes at the top of the slope close to the intercepting drainage ditch, the cracks and holes in the sinkholes are filled by spraying slurry, and then the sinkholes are grouted and masonry is carried out according to the design requirements to form a permeable layer, and drainage holes connected to the permeable layer are opened on both sides of the intercepting drainage ditch.

8. The method for treating sinkholes in loess slopes according to claim 6, characterized in that: When sealing the sinkholes, for the longitudinally connected sinkholes on the loess slope, the grouting and stone masonry method is used to transform the sinkholes into drainage channels.

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