Water seepage prevention treatment method for upper-layer stagnant water area of sand layer side slope

Abstract

The invention discloses an anti-seepage treatment method for an upper-layer stagnant water area of a sand layer slope, and belongs to the technical field of foundation pit engineering supporting. The method comprises the following steps: firstly, transversely partitioning and vertically layering a water seepage area; hammering short steel bars from the bottom of the stagnant water area by using a hand hammer, and welding to form an integral support; cleaning the sand layer above the horizontal steel bars to form a small side slope; laying a nylon net and a steel plate net and pressing a sand bag to form an inverted filter system; and finally, a steel plate net is laid, welded and smeared with cement mortar, and drainage holes are formed in the lowermost layer. The method does not need large equipment, adapts to narrow space, can give consideration to seepage prevention, drainage and supporting stability, can efficiently treat stagnant water on the upper layer of the sand layer slope, guarantees construction efficiency and slope safety, and reduces engineering cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foundation pit engineering support, in particular to a method for preventing water seepage in the upper water stagnation area of a sand layer slope. BACKGROUND

[0002] In the construction of municipal roads, highway bridges and foundation pit engineering, soil nailing wall support is widely used due to its economy and efficiency, especially in the northern region where construction is often carried out under waterless or dewatering conditions. However, when operating in the vicinity of old residential areas or areas with dense underground pipelines, local upper water stagnation can easily cause sand flow in the sand layer, leading to difficulties in slope protection construction, reduced efficiency, and increased costs. The use of dewatering wells for treatment has the problems of engineering scheduling difficulties and project delays, and in some construction sites, drilling machines cannot be set up due to space limitations, so there is an urgent need for an emergency anti-seepage treatment technology that does not require large equipment. The existing methods for treating water seepage in slopes have obvious defects: some methods rely on large dewatering equipment and cannot be implemented in narrow spaces; some methods only focus on slope plugging and do not form a systematic operation mode in layers and blocks, which can easily lead to overall instability due to local water pressure accumulation; and a few layering treatment techniques lack targeted design of the anti-filtration structure, which can easily bring out sand particles during water discharge, causing the slope to be hollowed out, and it is difficult to balance timeliness and support stability. SUMMARY

[0003] The present application aims to solve the above problems and provides a method for preventing water seepage in the upper water stagnation area of a sand layer slope without the need for large mechanical equipment and suitable for narrow construction spaces.

[0004] The present application solves the problem by adopting the following technical solution: A method for preventing water seepage in the upper water stagnation area of a sand layer slope, which is carried out in the following steps: S1, Area division: the area of the sand layer slope where water seepage occurs in the upper water stagnation area is divided horizontally and vertically, and the vertical layering thickness is determined according to the severity of water seepage and sand flow; S2, Steel bar arrangement: short steel bars with the same specifications as the steel bars on the slope surface of the soil nailing wall are used, starting at the bottom of the upper water stagnation area, and hammered into the lowermost layer in the order of vertical first and then horizontal, and the steel bars are electrically welded at the intersection points, and the steel bars between the blocks are also welded to form a whole support structure; S3, Slope surface cleaning: the sand layer above the horizontal steel bars is cleaned, the cleaning range includes a triangular area formed between the upper 1 / 2 depth in the longitudinal direction above the horizontal steel bars and the top of the adjacent upper layer, so that part of the horizontal steel bars is exposed, and a small slope is formed above the horizontal steel bars; S4, Anti-filtration layer laying: nylon mesh and steel mesh are laid on the exposed horizontal steel bars and the slope surface of the small slope, the nylon mesh is attached to the slope surface of the small slope, the steel mesh is covered on the outer side of the nylon mesh, and sand bags are pressed on the outer side of the steel mesh to form a multi-layer anti-filtration system; S5, surface treatment: the outside of the sand bag is arranged in order to be consistent with the slope surface, and after the completion of the layering treatment, the upper layer construction is circularly carried out, until the entire water permeable area is treated, the steel mesh is laid again on the outside of the sand bag, and the steel mesh is spot welded with each layer of reinforcing steel; the cement mortar is applied to the slope protection of the soil nail wall with the same strength grade, and the water drainage hole is arranged when the lowermost layer is constructed.

[0005] Further, in S1, the vertical layering thickness is less than or equal to 600 mm, when the water seepage and sand flow are serious, the layering thickness is reduced by densifying the reinforcing steel, and is controlled between 150 mm and 200 mm; the layering thickness is flexibly adjusted according to the actual situation of water seepage and sand flow, so that the layering treatment is more suitable for the site conditions, and the problem that the uniform thickness is difficult to adapt to different severity areas is avoided.

[0006] Further, in S4, the nylon mesh is laid in two layers, and the nylon mesh with a mesh size of 80-120 is selected; the sand particles are more effectively blocked, while the water is normally permeated and discharged, the loss of sand particles with water during water drainage is reduced, the stability of the internal structure of the slope is maintained, and the voids in the internal slope caused by the loss of sand particles are avoided.

[0007] Further, in S5, the filter pipe is inserted into the water drainage hole, and the filter pipe is wrapped with geotextile; the sand particles in the water are further filtered to prevent the loss of sand particles with water.

[0008] Further, a water guide groove is arranged at the bottom of the slope, and a water collecting pit is dug at the bottom of the slope, the water flowing out of the water drainage hole is guided into the water collecting pit through the water guide groove, and the water is cleaned by the drainage pump arranged in the water collecting pit at regular intervals; the water is prevented from accumulating at the bottom of the slope, the soaking of the soil at the bottom of the slope by the water is reduced, and the risk of instability of the slope due to the softening of the soil at the bottom is reduced.

[0009] The application adopting the above technical scheme has the following outstanding features compared with the prior art: The method has the advantages that: 1. The method does not rely on large mechanical equipment, and short steel bars are hammered into the simple operation through a hand hammer, which is perfectly suitable for narrow construction spaces such as old community periphery and underground pipeline dense area, solves the problem that traditional dewatering wells cannot be arranged due to site restrictions, greatly reduces the construction scheduling difficulty, and guarantees the construction progress. 2. A systematic processing mode of horizontal block and vertical layer is adopted, combined with the steel bar arrangement in the vertical direction first and then in the horizontal direction and welded into an integral support structure, different water seepage and serious sand flow areas are dealt with, local water pressure accumulation is avoided to cause overall instability, and the slope support stability is improved. 3. A small slope is formed by slope cleaning, a multi-layer reverse filtration system composed of nylon net, steel sheet and sand bag is matched, effective anti-seepage is realized, and the emptying of the slope caused by the sand particles brought out by the water discharge is prevented, and the cement mortar finishing and water discharge hole setting are combined, the impermeability, drainage and support strength are considered, in the emergency processing scene, the construction timeliness and the slope safety are efficiently balanced, the engineering cost is reduced, and the defects of single sealing or imperfect layered processing of the existing method are solved. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 The figure is a schematic diagram of the main body of the embodiment of the present application; In the figure, the marks are: upper water storage area 1, slope bottom 2, vertical steel bar 3, horizontal steel bar 4, small slope 5, sand bag 6, slope 7, water guide groove 8, water collecting pit 9. DETAILED DESCRIPTION

[0011] The present application will be further described below in combination with the embodiments, and the purpose is only to better understand the content of the present application, therefore, the examples do not limit the protection scope of the present application.

[0012] Reference Figure 1 A sand layer slope upper water storage area anti-seepage water treatment method is carried out according to the following steps: S1, region division: the upper water storage area 1 of the sand layer slope 7 appears water seepage, and the upper water storage area 1 is processed in horizontal block and vertical layer, and the vertical layer thickness is determined according to the water seepage and serious sand flow; S2, steel bar arrangement: short steel bars with the same specifications as the soil nailing wall slope steel bars are used, starting from the bottom of the upper water storage area 1, and the steel bars are hammered into the lowermost layer in the order of vertical first and then horizontal, wherein the vertical steel bars are vertical steel bars 3, and the horizontal steel bars are horizontal steel bars 4, the steel bars are welded at the intersection position, and the steel bars between the blocks are also welded to form an integral support structure; S3, slope cleaning: the sand layer above the horizontal steel bars 4 is cleaned, the cleaning range includes the depth of 1 / 2 in the longitudinal direction above the horizontal steel bars 4 and the triangular area formed between the top of the adjacent upper layer, so that the horizontal steel bars 4 are partially exposed, and a small slope 5 is formed above the horizontal steel bars 4; S4, filter layer laying: nylon net, steel mesh are laid on the exposed horizontal steel bars 4 and the small slope 5 surface, the nylon net is attached to the small slope 5 surface, the steel mesh is covered outside the nylon net, and the sand bag 6 is pressed outside the steel mesh, forming a multi-layer filter system; S5, surface treatment: the outside of the sand bag 6 is arranged in order to keep consistent with the slope 7 surface, after the completion of the layering treatment, the upper layer construction is carried out, until the entire upper layer waterlogging area 1 is treated, the steel mesh is laid outside the sand bag 6 again, and the steel mesh is spot welded with each layer steel bar; the cement mortar is used for finishing, which has the same strength grade as the soil nailing wall slope protection, and the drainage hole is arranged when the lowermost layer is constructed. The vertical layering thickness is less than or equal to 600mm, when the water seepage and sand flow are serious, the layering thickness is reduced by increasing the vertical steel bars 3 and horizontal steel bars 4, and is controlled between 150mm-200mm; the layering thickness is flexibly adjusted according to the actual situation of water seepage and sand flow in the upper layer waterlogging area 1, so that the layering treatment is more suitable for the site conditions, and the problem that the uniform thickness is difficult to adapt to different severity areas is avoided. The nylon net is laid in two layers, and the nylon net with 80-120 meshes is selected; the nylon net more effectively blocks the sand particles on the small slope 5 surface, while ensuring the normal penetration of water, reducing the loss of sand particles with water during drainage, maintaining the stability of the internal structure of the slope 7, and avoiding the voids in the internal structure of the slope 7 caused by the loss of sand particles. The filter pipe is inserted into the drainage hole, and the filter pipe is wrapped with geotextile; the sand particles in the water are further filtered during the drainage process, preventing the loss of sand particles with water, and ensuring the integrity of the soil in the slope 7. The water guide groove 8 is arranged at the bottom of the slope 7, i.e. the slope bottom 2, and the water collecting pit 9 is dug at the slope bottom 2, the water flowing out of the drainage hole is guided into the water collecting pit 9 through the water guide groove 8, and is cleaned regularly through the drainage pump arranged in the water collecting pit 9; the water is prevented from accumulating at the slope bottom 2, the soaking of the soil at the bottom of the slope 7 by water is reduced, and the risk of instability of the slope 7 due to the softening of the soil at the bottom is reduced.

[0013] The method described in the application does not rely on large mechanical equipment, through the simple operation of hammering short steel bars, it is perfectly suitable for narrow construction space such as the surrounding of old community and dense underground pipeline area, solves the problem that traditional dewatering well cannot be laid due to site restrictions, greatly reduces the difficulty of construction scheduling, and guarantees the progress of construction period. Secondly, the systematic processing mode of horizontal block and vertical layer is adopted, combined with the steel bar layout from vertical to horizontal and welded into an integral support structure, to deal with different water seepage and serious sand flow areas, avoid the overall instability caused by local water pressure accumulation, and improve the stability of slope support. Thirdly, through slope cleaning to form a small slope, combined with the multi-layer filtration system composed of nylon net, steel mesh and sand bag, it can not only effectively prevent seepage, but also prevent the sand particles from being carried out by the drainage, causing the slope to be hollowed out. At the same time, combined with the setting of cement mortar finishing and drainage hole, it takes into account the impermeability, drainage and support strength, ensures the efficient balance between construction timeliness and slope safety in the emergency processing scene, reduces the engineering cost, and solves the defects of single sealing or imperfect layered processing of the existing method.

[0014] The above only describes the preferred embodiments of the application, and does not limit the scope of the application, and any equivalent changes made by applying the content of the specification and drawings of the application are included in the scope of the application.

Claims

1. A method for preventing seepage in the perched water area of ​​a sandy slope, characterized in that, Follow these steps: S1. Area division: The area of ​​sand slope with upper layer water retention and seepage is divided into horizontal blocks and vertical layers. The thickness of the vertical layer is determined according to the severity of seepage and sand flow. S2. Reinforcement Layout: Short steel bars of the same specifications as the soil nailing wall slope reinforcement are used. Starting from the bottom of the upper water-retaining area, the steel bars are driven into the lowest layer by hand hammer in the order of vertical first and then horizontal. The steel bars are welded together at the intersections immediately. The steel bars between each block are also welded to form an overall support structure. S3. Slope cleaning: Clean the sand layer above the horizontal reinforcement. The cleaning area includes the triangular area formed between the top of the adjacent upper layer and the depth of the horizontal reinforcement in the longitudinal direction of 1 / 2. This exposes part of the horizontal reinforcement and forms a small slope above the horizontal reinforcement. S4. Laying of filter layer: Nylon mesh and steel mesh are laid on the top of the exposed horizontal steel bars and on the slope surface of the small slope. The nylon mesh is attached to the slope surface of the small slope, and the steel mesh is covered on the outside of the nylon mesh. Sandbags are pressed on the outside of the steel mesh to form a multi-layer filter system. S5. Surface treatment: Smooth the outside of the sandbags to match the slope surface. After the first layer is completed, repeat the next layer construction until the entire seepage area is treated. Then, lay steel mesh on the outside of the sandbags again and weld the steel mesh to the intersection of the reinforcing bars in each layer. Use cement mortar with the same strength grade as the soil nailing wall slope protection to apply the surface, and set drainage holes when constructing the lowest layer.

2. The method for preventing seepage in the perched water area of ​​a sandy slope according to claim 1, characterized in that: In S1, the vertical layer thickness is less than or equal to 600 mm. When water seepage and sand flow are severe, the layer thickness is reduced by increasing the reinforcement, and controlled between 150 mm and 200 mm.

3. The method for preventing seepage in the perched water area of ​​a sandy slope according to claim 1, characterized in that: In S4, the nylon mesh is laid in two layers, using 80-120 mesh nylon mesh.

4. The method for preventing seepage in the perched water area of ​​a sandy slope according to claim 1, characterized in that: In S5, a filter pipe is inserted into the drainage hole, and the root of the filter pipe is wrapped with geotextile.

5. The method for preventing seepage in the perched water area of ​​a sandy slope according to claim 1, characterized in that: A water guide channel is installed at the bottom of the slope, and a water collection pit is dug at the bottom of the slope. The water flowing out of the drainage hole is guided into the water collection pit through the water guide channel, and is cleaned regularly by a drainage pump installed in the water collection pit.

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