Karst area road emergency rescue method

Abstract

The invention discloses a karst area road emergency rescue method. The method comprises the steps that a geological radar is adopted to scan a stratum below a road to obtain geological exploration data; based on geological exploration data, dividing a soil body between the road and the deep foundation pit into a plurality of risk areas with different grades of high, medium and low; based on different grades, different supporting measures are adopted for the risk areas, double rows of scaffold steel pipes are arranged in the soil bodies of the high-risk areas in a driving mode, single rows of scaffold steel pipes are arranged in the soil bodies of the medium-risk areas in a driving mode, each row of scaffold steel pipes are arranged in the length direction of the road, and grouting holes are formed in the scaffold steel pipes; grouting is conducted on the scaffold steel pipes so that grout can be injected into the soil body through the grouting holes to be solidified to form a reinforcing body, and in the low-risk area, pouring is conducted on the soil body of the low-risk area to form the concrete retaining wall. The problems that deep foundation pit construction close to a road damages the road, and conventional road emergency rescue measures are high in cost and long in construction period are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and particularly relates to a method for emergency rescue of roads in karst areas. Background Art

[0002] With the intensive construction of cities, the deep foundation pit projects near roads are increasing day by day. Limited by the narrow construction space, the excavation of deep foundation pits near roads is likely to cause problems such as settlement of surrounding roads, collapse of retaining walls, and underground cavities. Especially in karst geological areas, the soil stability is poor and the backfill soil is loose, further aggravating the risks.

[0003] In order to avoid the damage to adjacent roads, measures such as micro steel pipe piles, supporting structures, and grouting reinforcement are often used for emergency rescue. However, the existing road emergency rescue technologies have the following defects:

[0004] 1. Traditional micro steel pipe piles: They need to be customized and purchased, with high costs (about 500 yuan / meter) and long supply cycles (≥7 days), which cannot meet the timeliness requirements of emergency rescue.

[0005] 2. Conventional support technologies: Such as steel sheet piles or concrete retaining walls, the construction is complex (requiring large machinery), the cycle is long (3 - 5 days), and it is difficult to adapt to the dynamic changes of underground cavities in karst areas.

[0006] 3. Blind areas of grouting reinforcement: Ordinary grouting processes cannot accurately fill underground cavities, resulting in insufficient support strength and high risk of secondary collapse.

[0007] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0008] To overcome the defects existing in the prior art, the present invention provides a method for emergency rescue of roads in karst areas to solve the problems of damage to roads caused by the construction of deep foundation pits near roads and the high costs and long construction cycles of conventional road emergency rescue measures.

[0009] To achieve the above object, a method for emergency rescue of roads in karst areas is provided, including the following steps:

[0010] Use ground penetrating radar to scan the strata under the road to obtain geological exploration data;

[0011] Based on the geological exploration data, divide the soil between the road and the deep foundation pit into multiple risk areas with different levels of high, medium, and low.

[0012] Based on different levels, different support measures are adopted for the risk areas respectively. In the high-risk area, double-row scaffolding steel pipes are driven into the soil of the high-risk area. In the medium-risk area, single-row scaffolding steel pipes are driven into the soil of the medium-risk area. Each row of scaffolding steel pipes is arranged along the length direction of the road. The scaffolding steel pipes are provided with grouting holes, and the soil is consolidated to form a reinforced body by injecting slurry through the grouting holes into the soil. In the low-risk area, a concrete retaining wall is poured in the soil of the low-risk area.

[0013] Further, the hole opening rate of the scaffolding steel pipe is 15% - 20%.

[0014] Further, the spacing of the scaffolding steel pipes is 500 mm.

[0015] Further, the slurry includes cement, accelerator and water, and the mass ratio of the cement: the water: the accelerator is 1:0.4:0.05.

[0016] Further, the grouting pressure of the scaffolding steel pipe is 1.5 - 2.0 MPa.

[0017] The beneficial effect of the present invention is that the emergency rescue method for roads in karst areas of the present invention uses local materials, utilizes the opening and modification of scaffolding steel pipes at the construction site, quickly completes the material preparation, and can quickly respond to the emergency rescue needs of roads.

[0018] Compared with the traditional micro steel pipe piles, the cost of the emergency rescue method for roads in karst areas of the present invention is high. By using the modified scaffolding steel pipe piles, the cost is only 10% of the cost of the traditional micro steel pipe piles.

[0019] The emergency rescue method for roads in karst areas of the present invention divides the risk levels according to the geological exploration data, dynamically divides the areas for support, and differentially designs the support parameters.

[0020] The emergency rescue method for roads in karst areas of the present invention adopts high-pressure grouting combined with an accelerator. The initial setting time of the slurry is short, which can effectively seal the karst fissures. The double-row pile design provides support, and the anti-overturning safety factor is high. Description of the Drawings

[0021] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects and advantages of the present application will become more obvious:

[0022] Figure 1 It is a schematic plan view of the support structure of the road in the karst area and the deep foundation pit of the embodiment of the present invention.

[0023] Figure 2 It is a schematic view of the support measures in the high-risk area of the embodiment of the present invention.

[0024] Figure 3 Schematic diagram of the support measures for the medium-risk area in the embodiment of the present invention.

[0025] Figure 4 Schematic diagram of the support measures for the low-risk area in the embodiment of the present invention. Detailed implementation manners

[0026] The following further elaborates on the present application in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are merely for explaining the related invention rather than limiting the invention. Additionally, it should be noted that for the convenience of description, only the parts related to the invention are shown in the drawings.

[0027] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will elaborate on the present application in detail with reference to the drawings and embodiments.

[0028] Refer to Figures 1 to 4 As shown, the present invention provides a method for emergency rescue and repair of roads in karst areas, including the following steps:

[0029] S1. Use a ground-penetrating radar to scan the strata below the road 5 to obtain geological exploration data.

[0030] S2. Based on the geological exploration data, divide the soil body between the road 5 and the deep foundation pit into multiple risk areas of different levels, including high, medium, and low levels.

[0031] Use a ground-penetrating radar to scan the soil body within the range of 0 - 10 m below the road and divide it as follows:

[0032] (1) High-risk area: There are underground cavities.

[0033] (2) Medium-risk area: The soil body is loose.

[0034] (3) Low-risk area.

[0035] S3. Based on different levels, adopt different support measures for different risk areas. In the high-risk area, drive double-row scaffolding steel pipes 1 into the soil body of the high-risk area. In the medium-risk area, drive single-row scaffolding steel pipes 1 into the soil body of the medium-risk area. Each row of scaffolding steel pipes 1 is arranged along the length direction of the road 5. The scaffolding steel pipes 1 are provided with grouting holes, and the slurry is injected into the soil body through the grouting holes of the scaffolding steel pipes 1 to form a solidified body. In the low-risk area, pour a concrete retaining wall in the soil body of the low-risk area.

[0036] In this embodiment, a support structure is formed at the outer edge of the deep foundation pit. The support mechanism includes retaining piles and a ring beam 3 cast on the retaining piles. The support measures are constructed in the soil body between the ring beam and the road 5. A retaining fence 2 is provided on the side of the soil body close to the road. A foundation 21 is cast in the soil body. The retaining fence is installed on the foundation.

[0037] In this embodiment, at least one row of the steel pipes of the double-row scaffolding supports on the foundation of the enclosure. The upper ends of the steel pipes of the scaffolding are embedded in the foundation of the enclosure. The foundation of the enclosure adopts a concrete structure.

[0038] In the high-risk area, double-row steel pipes with a diameter of Φ75mm and a spacing of 500mm are set up, and the length of the steel pipes of the scaffolding is 6m.

[0039] In the medium-risk area, single-row steel pipes with a diameter of Φ75mm and a spacing of 500mm are set up, and the length of the steel pipes of the scaffolding is 6m.

[0040] As a preferred embodiment, the slurry includes cement, a quick-setting agent and water, and the mass ratio of cement: water: quick-setting agent is 1:0.4:0.05.

[0041] The grouting pressure of the steel pipe 1 of the scaffolding is 1.5 to 2.0 MPa.

[0042] In the low-risk area, a C20 concrete retaining wall is used for support. The upper width of the retaining wall is 800mm, the lower width is 1500mm, and the height is 1800mm.

[0043] In this embodiment, the steel pipes of the scaffolding are locally reformed into retaining piles on the spot, and the cost is only 10% of that of the traditional micro-piles.

[0044] The steel pipes of the scaffolding are perforated in a plum blossom shape: holes with a diameter of Φ12mm are opened on the steel pipes of the scaffolding with a size of Φ48×3.2mm, the hole spacing is 300mm, and the hole opening rate is 15% to 20%.

[0045] After the steel pipes of the scaffolding are perforated, the perforated steel pipes of the scaffolding are inserted into the Φ75mm drill holes, the hole position spacing is 500mm, and the verticality deviation is ≤1%.

[0046] Prepare the slurry. The specific ratio of the slurry is: P.O42.5 cement: water: quick-setting agent = 1:0.4:0.05, and the grouting pressure is 1.5 to 2.0 MPa.

[0047] The grouting sequence: grout in sections from bottom to top, and the grouting volume V of each section = 1.2×the volume of the cavity (measured by ground penetrating radar).

[0048] In this embodiment, inclination sensors are arranged on the enclosure to monitor the displacement of the enclosure, and the displacement threshold is ≤3mm / hour.

[0049] Distributed optical fibers are used to monitor the pavement strain, and secondary grouting is started when it exceeds the limit.

[0050] The method for emergency rescue of roads in karst areas of the present invention uses local materials, utilizes the steel pipes of the scaffolding on the construction site to be perforated and refitted, quickly completes the material preparation, and can quickly respond to the emergency rescue needs of roads. Road emergency rescue is sudden and time-sensitive.

[0051] The emergency rescue method for roads in karst areas of the present invention has a higher cost compared to traditional micro steel pipe piles. By modifying the scaffolding steel pipe piles, its cost is only 10% of that of traditional micro steel pipe piles.

[0052] The emergency rescue method for roads in karst areas of the present invention divides the risk levels according to geological exploration data, dynamically partitions the support, and differentially designs the support parameters.

[0053] The scaffolding steel pipes of the emergency rescue method for roads in karst areas of the present invention adopt plum blossom-shaped openings combined with high-pressure grouting to achieve the coordinated force between the pile body and the soil, and the lateral displacement resistance stiffness is increased by 40%.

[0054] The emergency rescue method for roads in karst areas of the present invention adopts high-pressure grouting combined with a quick-setting agent, shortening the initial setting time of the slurry to 20 minutes, effectively plugging karst fissures, and providing support with a double-row pile design, having a high anti-overturning safety factor.

[0055] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A method for emergency rescue of roads in karst areas, characterized in that, It includes the following steps: Using ground penetrating radar to scan the strata under the road to obtain geological exploration data; Based on the geological exploration data, dividing the soil body between the road and the deep foundation pit into multiple risk areas with different levels of high, medium and low; Based on different levels, adopting different support measures for the risk areas respectively. In the high-risk area, driving double-row scaffolding steel pipes in the soil body of the high-risk area. In the medium-risk area, driving single-row scaffolding steel pipes in the soil body of the medium-risk area. Each row of scaffolding steel pipes is arranged along the length direction of the road. The scaffolding steel pipes are provided with grouting holes, and the slurry is injected into the soil body through the grouting holes of the scaffolding steel pipes to solidify and form a reinforced body. In the low-risk area, pouring a concrete retaining wall in the soil body of the low-risk area.

2. The method for emergency rescue of roads in karst areas according to claim 1, characterized in that, The opening rate of the scaffolding steel pipe is 15% - 20%.

3. The method for emergency rescue of roads in karst areas according to claim 2, characterized in that, The spacing of the scaffolding steel pipes is 500 mm.

4. The method for emergency rescue of roads in karst areas according to claim 1, characterized in that, The slurry includes cement, accelerator and water, and the mass ratio of cement: water: accelerator is 1:0.4:0.

05.

5. The method for emergency rescue of roads in karst areas according to claim 4, wherein The grouting pressure of the scaffolding steel pipe is 1.5 - 2.0 MPa.

Images