Rapid landslide slope fixing construction method

Abstract

The invention discloses a rapid landslide slope fixing construction method, which belongs to the technical field of slope fixing, and comprises the following steps: S1, selecting clay, cement and water, stirring and mixing to form cement soil; s2, cement soil is sprayed to the surface, exposed out of the collapse, of the upper side slope; s3, collapse bodies are cleaned; s4, cement soil is sprayed to the surface, exposed after the collapse bodies are cleaned, of the lower side slope; the surface of a collapsed or unstable slope can be rapidly solidified, a protective shell is formed, rainwater permeation is effectively prevented, and a good foundation is laid for follow-up permanent slope protection construction; and meanwhile, the construction safety risk of personnel is reduced, the collapse slope is rapidly treated, and the road is guaranteed to recover traffic as soon as possible.

Description

Technical Field

[0001] This invention belongs to the field of slope stabilization technology, and specifically relates to a rapid slope stabilization construction method for collapsed slopes. Background Technology

[0002] Currently, the main engineering measures for slope reinforcement include grouting reinforcement, anchor bolt reinforcement, soil nailing reinforcement, and prestressed anchor cable reinforcement. Slope protection construction timelines generally fall into two categories: one is simultaneous excavation and support, where slope protection construction begins immediately after each layer of excavation is completed. The advantage is slope stability, reducing safety risks during slope excavation. The disadvantage is the long construction time, significantly impacting the overall project schedule, and it is unsuitable for slopes that have already collapsed. The other approach involves erecting sloping scaffolding for slope protection construction after excavation. The advantage is that it does not disrupt the project's linear construction schedule. The disadvantages are the added scaffolding construction process, the risk of scaffolding collapse, and the safety risks of workers having to work close to the slope after prolonged exposure. Similarly, it is unsuitable for slopes that have already collapsed.

[0003] With the continuous rainfall in recent years, especially in special areas such as slopes with mud-and-gravel geological structures, slopes with mud-and-gravel geological structures, and strongly weathered rock slopes with developed rock fissures, rainwater seeps into the mountainside along the slope surface or top. Long-term soaking of slopes by rainwater causes frequent landslides, and in severe cases, can trigger debris flows. Landslide-affected slopes are classified into various types depending on the geological conditions, such as: steep upper slopes with gentle lower slopes, slopes with overhanging structures, vertical slopes, and slopes with cracks in the rock mass. If temporary protection of the steep upper slope is not immediately implemented, clearing the landslide body poses a significant safety risk. For slopes that have already collapsed or show signs of instability, rapid surface solidification is necessary to form a protective shell, preventing continuous rainwater infiltration and providing favorable conditions for subsequent permanent slope protection construction.

[0004] Existing slope reinforcement technologies are not suitable for rapid slope protection of this type of slope. Long-term slope protection construction will affect road traffic, and prolonged exposure of the slope will easily cause secondary disasters. In addition, when using conventional slope reinforcement construction, personnel need to be close to the collapsed slope. Vibration and disturbance of the slope during construction can easily cause secondary disasters at the collapsed slope, increasing the safety risks for construction personnel. Therefore, a construction technology for long-distance slope protection and rapid slope stabilization is needed. Summary of the Invention

[0005] The purpose of this invention is to provide a rapid slope stabilization method for slopes in special areas with complex geological conditions, such as slopes with mud-stone geological structures, slopes with mud-stone geological structures, and strongly weathered rock slopes with developed rock fissures, where landslides have occurred and slopes are unstable.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a rapid slope stabilization construction method for collapsed slopes, comprising the following steps: S1. Select clay, cement and water, mix them to form cement soil; S2. Spray cement and soil onto the exposed upper slope surface of the collapsed area; S3. Clear the collapsed area; S4. Spray cement and soil onto the lower slope surface exposed after clearing the landslide.

[0007] Furthermore, the clay is sieved using a wire mesh with a aperture of 1.5cm-2cm.

[0008] Furthermore, the weight ratio of cement to clay is 12:100; the weight ratio of water to clay is 1:2.

[0009] Further, step S1 includes the following steps: excavating a mixing tank at a road meeting platform or idle area; first, adding clay and cement into the mixing tank, and using a hydraulic backhoe to mix them multiple times to make the cement and clay evenly mixed; then adding water and mixing to form a gel-like cement-soil mixture.

[0010] Furthermore, in step S2, a hydroseeding machine is used to spray cement-soil, and a dump truck is used to carry the hydroseeding machine for mobile spraying.

[0011] Furthermore, in step S2, after one spraying is completed, a drone equipped with a camera and an infrared thermal imager is used to detect the slope, and the detected defects are sprayed again.

[0012] Furthermore, in step S2, before spraying the cement soil, water is sprayed onto the upper slope surface.

[0013] Furthermore, the water spraying process employs high-pressure water mist and low-pressure water flow sequentially.

[0014] Furthermore, in step S3, it is determined whether a construction access road needs to be built based on the height of the landslide. If the slope height is higher than 6m, a hydraulic backhoe is used to build the construction access road. If it is lower than 6m, the hydraulic backhoe can be used directly for hazard removal.

[0015] Furthermore, in step S4, slope cleaning and water spraying are carried out sequentially before spraying cement soil; slope cleaning includes removing residual loose soil, gravel and debris to make the slope surface smooth.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention is mainly a rapid slope protection process after a landslide. The cement soil is mixed into a gel-like substance and sprayed from a distance using a greening spraying device to stabilize the slope and extend to the outer top of the slope. This process seals the entire slope, solidifies the slope and the top, and prevents slope collapse caused by rainwater seepage or injuries caused by falling rocks. This invention is mainly applied to the construction of temporary slope protection after a high slope collapse, avoiding secondary disasters caused during the clearing of the collapsed body. After the rapid slope protection construction of the collapsed slope is completed, personnel and machinery can carry out the clearing of the collapsed body in a safe state, and the road can be opened to traffic. Detailed Implementation

[0017] The present invention will now be described in further detail. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention; that is, the described embodiments are merely some, not all, of the embodiments of the present invention.

[0018] This embodiment provides a rapid slope stabilization construction method for collapsed slopes, including: (1) Cement-soil mixing Excavate a mixing tank at the road meeting platform / idle area. The size of the mixing tank should be controlled at a depth of 1.5 to 2 meters and a bottom area of ​​not less than 4 square meters to ensure that there is enough space to hold the materials and to mix them thoroughly.

[0019] Clay, sieved using a wire mesh (1.5cm-2cm aperture), is poured into the mixing tank. The sieved clay particles are evenly dispersed during the mixing and spraying of the cement-soil mixture, effectively ensuring its uniformity and fluidity, laying a solid foundation for subsequent construction. The clay selected is local soil with very little sand, good cohesion, and minimal water penetration, exhibiting good plasticity. Clay with a plasticity index between 15 and 20, combined with the aforementioned particle size sieving standards, achieves an optimal balance between early strength development and later durability in the cement-soil mixture, further optimizing its performance indicators.

[0020] P.042.5 cement in bags, with a clay weight ratio of 12 / 100, is thoroughly mixed with the clay to ensure uniform mixing. After adding water, the mixture is transported to the hydroseeding machine location for cement-soil slope stabilization. The water weight is controlled to be 1 / 2 of the clay weight. The mixture is then stirred to form a gel-like substance to create cement-soil. All performance indicators of the bagged P.042.5 cement should meet the requirements of the national standard GB175-2007 "General Portland Cement". Upon arrival at the site, the cement's strength, setting time, and soundness are tested.

[0021] Add clay and cement to the mixing tank and use a hydraulic backhoe to mix them multiple times. During the mixing process, use the hydraulic backhoe to mix at least 3 to 5 times, with each mixing time not less than 5 minutes, so that the cement and clay are fully mixed evenly and avoid local cement content that is too high or too low.

[0022] The cement ratio was determined from the perspective of matching the mechanical properties of cement-soil with slope stability. The focus was on analyzing the compatibility of shear strength, compressive strength, and other indicators of cement-soil with the required strength of the collapsed slope under different cement ratios. Tests were conducted with cement ratios of 8%, 10%, 12%, and 14%, and the relevant data are as follows: |Cement ratio (%)|7-day unconfined compressive strength (MPa)|Internal friction angle (°)|Cohesion (kPa)|Maximum slope height that can be withstood (m)|; |8|0.50|25|25|45|; |10|0.65|28|32|55|; |12|0.70|30|35|60|; |14|0.72|31|36|62|; The experimental data shows that with the increase of cement ratio, the 7-day unconfined compressive strength, internal friction angle, and cohesion of cement-soil all show an upward trend, and the maximum slope height that can be withstood also increases accordingly. When the cement ratio increases to 14%, the 7-day unconfined compressive strength increases to 0.72 MPa, the internal friction angle reaches 31°, the cohesion increases to 36 kPa, and the maximum slope height that can be withstood is 62 m, but the rate of increase of each indicator has slowed significantly compared to when it is 12%.

[0023] Based on the actual conditions of the collapsed slope, the slope in question is 60m high. When the cement ratio is 12%, the 7-day unconfined compressive strength reaches 0.7MPa, the internal friction angle is 30°, and the cohesion is 35kPa. The maximum slope height it can withstand is 60m, which fully meets the temporary slope stabilization strength requirements for a 60m high collapsed slope. Cement-soil with ratios of 8% and 10% has mechanical properties lower than the minimum values ​​required for slope stability, and cannot guarantee slope safety. While cement-soil with a 14% ratio has better mechanical properties, it exceeds the actual required strength and increases cement usage, leading to higher costs.

[0024] Furthermore, in terms of material deformation performance, a 12% cement-soil mixture can deform in coordination with the slope rock mass under stress, avoiding cracking due to excessive stiffness differences. In contrast, a 14% mixture has higher stiffness and is prone to cracking under slight slope deformation, thus affecting the slope stabilization effect.

[0025] Considering the matching of the above mechanical properties with slope stability, the weight ratio of cement to clay was determined to be 12 / 100. This ratio satisfies the strength requirements for resisting shallow slope slippage in the initial stage of rapid slope stabilization, while also ensuring a slump of ≤25cm during wet spraying, guaranteeing good plasticity and spray adhesion. Furthermore, the initial setting time of the cement-soil mixture under this ratio is controlled within 4-6 hours, allowing for a reasonable time window for construction operations and enabling rapid manifestation of slope reinforcement effects.

[0026] After ensuring the cement and clay are thoroughly mixed, add mixing water according to the specified ratio. Once mixed, the resulting cement-soil mixture is loaded into a hydroseeding machine and transported by dump truck to the slope protection construction section for spraying. This method of first ensuring the cement and clay are fully mixed before adding water avoids situations where the cement content is too high or too low in certain areas.

[0027] (2) Spraying cement soil Before spraying cement and soil, the exposed upper slope surface after the collapse should be sprayed with water 1-2 times to ensure it is kept moist and without obvious watermarks, so as to facilitate the adhesion of cement and soil to the slope surface.

[0028] Before performing cement-soil spraying, the slope surface must undergo rigorous pretreatment. High-pressure water mist and low-pressure water jets are sprayed alternately, with the high-pressure water mist pressure set at 8–10 MPa and a spraying duration of 3–5 minutes; the low-pressure water jet pressure is controlled at 0.5–1 MPa and a spraying duration of 2–3 minutes. During the alternating spraying process, the water flow impact energy formula E=mv is applied. 2 / 2 (where m is the water flow mass per unit time and v is the water flow velocity), by precisely controlling the pressure and spraying time of the high-pressure water mist and low-pressure water flow, the impact energy of the high-pressure water mist is maintained at 50–80 J / m², and the impact energy of the low-pressure water flow is maintained at 5–10 J / m². Within this energy range, the high-pressure water mist can effectively impact the slope surface, removing surface soil, debris, and loose rocks, while forming tiny grooves on the slope surface; the low-pressure water flow further moistens the slope surface, achieving an ideal moist state without obvious watermarks. This pretreatment method can significantly improve the mechanical interlocking force between cement-soil and the slope surface. Experiments have verified that it can increase the bond strength between cement-soil and the slope surface by 30%, providing a good foundation for subsequent cement-soil spraying.

[0029] A professional hydroseeding machine is selected, which can be mounted on a dump truck for mobile spraying, accelerating the spraying rate. The hydroseeding machine used is the YGP4330-50-6 professional hydroseeding machine, and the dump truck is the Chenglong brand ZZ3257V414HE1 model. The hydroseeding machine and the dump truck together form a mobile spraying operation platform. The hydroseeding machine has a powerful power system and precise conveying control device, while the dump truck has good off-road performance and load-bearing capacity. The combination of the two enables efficient and flexible mobile spraying operations, significantly improving construction efficiency.

[0030] After the equipment is in place, adjust the pressure and air volume of the delivery pump according to the slope height and the parking position of the muck truck. Based on the power of the hydroseeding machine, it can perform cement-soil spraying operations on slopes up to 60m high, ensuring the mixture is evenly sprayed onto the slope surface and completing the cement-soil spraying operation in one go from top to bottom. For 60m high slope operations, the initial pressure of the delivery pump is set to 2.9-3.0MPa (error ≤ ±0.05MPa). After the horizontal distance between the muck truck and the slope toe exceeds 15m, the pressure increases by 0.2MPa for every additional 5m, with a maximum of 3.5MPa; the air volume is 15000±500m³ / h.

[0031] After the final sprayed cement-soil construction is completed, drone technology is used to inspect the slope solidification effect, mainly to check whether there are cracks on the slope surface, whether the thickness of the sprayed cement-soil is uniform, and whether re-spraying is needed.

[0032] The drone is equipped with a 20-megapixel high-resolution camera and an infrared thermal imager with a temperature resolution of 0.05℃ for comprehensive inspection. The high-resolution camera can clearly capture the details of the slope surface and identify cracks; the infrared thermal imager can detect temperature differences caused by defects inside the slope and discover potential problems such as hollowness and cracks.

[0033] Once the slope protection is completed, the landslide cleanup operation can begin, and the results have been excellent.

[0034] (3) Clearing of landslide debris After completing the temporary stabilization of the steep slope, machinery and personnel can be organized to carry out the landslide clearing work. The construction access road needs to be built based on the height of the landslide. If the slope height is higher than 6m, a hydraulic backhoe can be used to build the access road. If it is lower than 6m, the hydraulic backhoe can be used directly for hazard removal. Areas on the upper slope with overhanging trees, exposed tree roots, and areas prone to secondary landslides should be cleared to avoid secondary landslides caused by overhanging objects, trees, and other dangerous areas, thereby reducing the safety risks during the landslide construction.

[0035] (4) Spraying cement soil After clearing the landslide area, the exposed lower slope was treated with slope protection and water spraying, followed by shotcrete slope protection construction.

[0036] Slope Treatment: First, inspect the cleaned lower slope surface, removing any remaining loose soil, gravel, and debris to ensure a smooth surface with no more than 10cm of unevenness in any localized area (within 1 square meter). If any pits or cavities exist on the slope, backfill them with the same grade of soil. Seal any cracks on the slope with mud slurry to prevent cement-soil loss during spraying. Before spraying the cement-soil mixture, thoroughly spray the lower slope surface with water 1-2 times to ensure it remains moist without visible watermarks, facilitating adhesion between the cement-soil mixture and the slope surface.

[0037] Compared to traditional slope protection techniques, this invention significantly shortens the construction cycle through the application of a mobile spraying system and drone-based rapid detection and evaluation technology. Actual engineering verification has shown that construction efficiency is increased by over 60%, enabling the stabilization and clearing of collapsed slopes in the shortest possible time, ensuring rapid road reopening, reducing the impact of slope collapses on traffic, and providing strong support for disaster relief and people's normal production and daily life.

[0038] By employing long-distance spraying operations, construction workers do not need to approach the collapsed area, effectively avoiding injuries caused by secondary slope collapses, rockfalls, and other factors, reducing personnel safety risks by more than 70%. Simultaneously, the planning of access roads and precise hazardous area clearing strategies further ensure the safety of personnel and equipment during construction.

[0039] In the cement-soil mixing process, a refined screening and proportioning design is adopted, combined with water proportioning technology, to ensure stable cement-soil quality. The innovative slope pretreatment process significantly improves the bonding strength between cement-soil and the slope, increasing the bonding strength between cement-soil and the slope by 30%, effectively guaranteeing the quality of the slope protection project and ensuring the long-term stability and reliability of the slope protection structure.

[0040] For landslide slopes with various complex geological structures, such as mud-and-stone geological structures, mud-and-stone geological structures, and strongly weathered rock slopes with developed rock fissures, this technology can effectively implement rapid slope stabilization treatment, significantly expanding the application scenarios of slope stabilization construction technology and having broad application value.

[0041] This embodiment was tested during the construction of the Guanghuapu Wind Farm project in Xing'an, Guangxi. The access road to the wind farm was partially widened and shared by the local village road construction project. Due to continuous rainfall and complex geological conditions, the slope of the wind farm road collapsed to varying degrees. Since this road is also the main road for local villagers, it is necessary to quickly complete the slope protection work after the collapse, clear the collapsed body, and restore the road to traffic.

[0042] The technical solutions and embodiments disclosed in this invention are merely illustrative of the concept of this invention and do not constitute a limitation of this invention. Any non-creative changes made to the technical details disclosed in this invention have the same inventive spirit as this invention and are within the protection scope of the claims of this invention.

Claims

1. A rapid slope stabilization construction method for collapsed slopes, characterized in that, Includes the following steps: S1. Select clay, cement and water, mix them to form cement soil; S2. Spray cement and soil onto the exposed upper slope surface of the collapsed area; S3. Clear the collapsed area; S4. Spray cement and soil onto the lower slope surface exposed after clearing the landslide.

2. The rapid slope stabilization construction method for collapsed slopes according to claim 1, characterized in that: The clay is sieved through a wire mesh with a aperture of 1.5cm-2cm.

3. The rapid slope stabilization construction method for collapsed slopes according to claim 1, characterized in that: The weight ratio of cement to clay is 12:100; the weight ratio of water to clay is 1:

2.

4. The rapid slope stabilization construction method for collapsed slopes according to claim 1, 2, or 3, characterized in that: Step S1 includes the following steps: excavating a mixing tank at a road meeting platform or idle area; first, adding clay and cement into the mixing tank and using a hydraulic backhoe to mix them multiple times to make the cement and clay evenly mixed; then adding water and mixing to form a gel-like cement-soil mixture.

5. The rapid slope stabilization construction method for collapsed slopes according to claim 1, characterized in that: In step S2, a hydroseeding machine is used to spray cement-soil, and a dump truck is used to carry the hydroseeding machine for mobile spraying.

6. The rapid slope stabilization construction method for collapsed slopes according to claim 1 or 5, characterized in that: In step S2, after one spraying is completed, a drone equipped with a camera and an infrared thermal imager is used to detect the slope and to re-spray the detected defects.

7. The rapid slope stabilization construction method for collapsed slopes according to claim 1 or 5, characterized in that: In step S2, before spraying cement soil, water is sprayed onto the upper slope surface.

8. The rapid slope stabilization construction method for collapsed slopes according to claim 7, characterized in that: The water spraying process uses high-pressure water mist and low-pressure water flow sequentially.

9. The rapid slope stabilization construction method for collapsed slopes according to claim 1, characterized in that: In step S3, it is determined whether a construction access road needs to be built based on the height of the landslide. If the slope height is higher than 6m, a hydraulic backhoe is used to build the access road. If it is lower than 6m, the hydraulic backhoe can be used directly for hazard removal.

10. The rapid slope stabilization construction method for collapsed slopes according to claim 1, characterized in that: In step S4, slope cleaning and water spraying are carried out in sequence before spraying cement soil; slope cleaning includes removing residual loose soil, gravel and debris to make the slope surface smooth.