Construction method and structure suitable for protection of red sandy mudstone waterlogged roadbed

Abstract

This invention relates to a construction method and structure suitable for the protection of red sandy mudstone subgrades exposed to water, comprising the following steps: obtaining a subgrade base that meets construction requirements; laying an impermeable geotextile on the subgrade base, and then laying a cement-clay composite sealing layer on the impermeable geotextile; constructing a retaining wall on the side of the cement-clay composite sealing layer closest to the bottom of the water body; constructing filling material in the retaining wall area; after the filling material has been formed, constructing a gravel edging layer, and laying a solid hexagonal block slope protection layer with impermeable geotextile on the outside of the gravel edging layer; and completing the subgrade protection construction. The beneficial effects of this invention are: by concentrating construction work on the structural layer at the top of the subgrade, the amount of earthwork and disturbance to the original foundation can be significantly reduced, the damage to the surrounding environment caused by construction can be reduced, and the construction period can be shortened; the dual impermeable system composed of the impermeable geotextile and the cement-clay composite sealing layer ensures the long-term dryness and stability of the subgrade bearing layer.

Description

Technical Field

[0001] This invention belongs to the field of roadbed engineering technology, specifically relating to a construction method and structure suitable for the protection of red sandy mudstone roadbeds submerged in water. Background Technology

[0002] As the load-bearing structure of highways and other transportation infrastructure, the stability and durability of the roadbed are fundamental to ensuring safe operation. In roadbed construction, red sandy mudstone, a typical soft rock with poor engineering properties, is widely distributed in certain regions of Southwest and South China. This type of rock contains hydrophilic minerals, which soften and disintegrate rapidly upon contact with water, resulting in a sharp decrease in strength. Under the influence of wet-dry cycles, it weathers quickly, easily leading to uneven settlement and slope collapse. For roadbeds located near water (such as reservoirs or rivers), water damage is particularly prominent.

[0003] The conventional methods used in the engineering field to treat this type of foundation are chemical solidification and replacement. Chemical solidification improves the soil by adding cement, lime, etc., but it has problems such as high cost, strict process control, insufficient long-term water stability, and the improvement effect being greatly affected by the original soil. Replacement requires the excavation and replacement of the poor soil and rock with high-quality materials. When the mudstone layer is deep, this leads to a large amount of earthwork, a sharp increase in cost, and serious damage to the ecological environment. Moreover, if the replacement is not thorough, the underlying untreated mudstone layer may still become a hidden danger.

[0004] Therefore, it is essential to provide a construction method and structure suitable for the protection of water-soaked roadbeds made of red sandy mudstone to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a construction method and structure suitable for the protection of water-soaked roadbeds made of red sandy mudstone, aiming to solve the problems of high investment, serious ecological damage, and long construction period associated with existing chemical solidification and replacement methods.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a construction method suitable for the protection of water-soaked roadbeds made of red sandy mudstone, comprising the following steps: Obtain a roadbed base that meets construction requirements; A geotextile was laid on the subgrade base, and a cement-clay composite sealing layer was laid on the geotextile. Construct a retaining wall on the side of the cement-clay composite seal layer closest to the bottom of the water body; Construction of infill material in the retaining wall area; After the filling material is formed, the gravel edging layer is constructed, and solid hexagonal blocks with impermeable geotextile are laid on the outside of the gravel edging layer for slope protection. Complete the construction of roadbed protection.

[0007] Furthermore, the filling material includes a permeable material and a preferred permeable material. The permeable material is located on both sides below the retaining wall, and the preferred permeable material is located on the upper side of the retaining wall and the cement-clay composite seal layer.

[0008] Furthermore, it also includes the following steps: The water-facing slope of the preferred permeable material is sloped, filled, and leveled at a slope ratio of 1:1.75.

[0009] Furthermore, it also includes the following steps: The gravel edging layer is set to correspond to the slope of the water-facing side slope of the preferred permeable material.

[0010] Furthermore, the thickness of the gravel edging layer is 1 meter.

[0011] Furthermore, the construction of the hexagonal block staggered joint masonry for the solid hexagonal block slope protection with impermeable geotextile.

[0012] Furthermore, the thickness of the cement-clay composite seal layer is 1 meter.

[0013] Furthermore, obtaining a roadbed base that meets construction requirements specifically includes the following steps: The loose stones and crops on the original ground were cleared away, and the surface covering was removed. After removing the overburden, steps are excavated within the cross-sectional area of ​​the roadbed; The exposed top surface of the red sandy mudstone layer after excavation was leveled and compacted to form a solid and flat roadbed base.

[0014] On the other hand, a protective structure adapted to a water-soaked roadbed of red sandy mudstone is provided, including an impermeable geotextile. The impermeable geotextile is laid on the roadbed base, and a cement-clay composite sealing layer is laid on the impermeable geotextile. A retaining wall is provided on the side of the cement-clay composite sealing layer near the bottom of the water body. The retaining wall area is filled with filling material, and a gravel edging layer is laid on the side of the filling material. A solid hexagonal block slope protection with impermeable geotextile is laid on the outside of the gravel edging layer.

[0015] The advantages of this invention compared to the prior art are: 1. By concentrating construction work on the structural layer at the top of the roadbed, the amount of earthwork and disturbance to the original foundation can be significantly reduced, the damage to the surrounding environment caused by construction can be reduced, and the construction period can be shortened. 2. The dual seepage prevention system, consisting of impermeable geotextile and cement-clay composite sealing layer, can effectively block the vertical infiltration of surface water and capillary water, prevent water from contacting the underlying red sandy mudstone, fundamentally avoid its softening upon contact with water, and ensure the long-term dryness and stability of the roadbed bearing layer. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a structure adapted to a water-soaked roadbed protection structure of red sandy mudstone, provided as an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. Impermeable geotextile; 2. Cement-clay composite sealing layer; 3. Retaining wall; 4. Filling material; 41. Permeable material; 42. Preferred permeable material; 5. Gravel edging layer; 6. Solid hexagonal block with impermeable geotextile slope protection; A. Original ground; B. Road slope; C. Road surface; D. Road centerline; E. Interception ditch; F. Roadside ditch; G. Water level. Detailed Implementation

[0018] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0019] This invention discloses a construction method suitable for the protection of water-saturated roadbeds made of red sandy mudstone, comprising the following steps: Obtain a roadbed base that meets construction requirements; A geotextile 1 is laid on the subgrade base, and a cement-clay composite sealing layer 2 is laid on the geotextile 1. Construct retaining wall 3 on the side of cement-clay composite sealing layer 2 closest to the bottom of the water body; Construction of filling material 4 is carried out in area 3 of the retaining wall; After the filling material is formed, the gravel edging layer 5 is constructed, and a solid hexagonal block plus impermeable geotextile slope protection 6 is laid on the outside of the gravel edging layer 5. Complete the construction of roadbed protection.

[0020] In this embodiment, by concentrating the construction work on the structural layer at the top of the roadbed, the amount of earthwork and disturbance to the original foundation can be significantly reduced, the damage to the surrounding environment caused by construction can be reduced, and the construction period can be shortened. The dual seepage prevention system composed of the seepage-proof geotextile 1 and the cement-clay composite sealing layer 2 can effectively block the vertical infiltration of surface water and capillary water, prevent water from contacting the underlying red sandy mudstone, fundamentally avoid its softening when exposed to water, and ensure the long-term dryness and stability of the roadbed bearing layer. In addition, the retaining wall 3 is set above the water level line G, with the road surface C above the filling material 4 and the road centerline D above the filling material 4, so that the main load is applied to the stable layer of the filling material 4.

[0021] In some embodiments, the filling material 4 includes a permeable material 41 and a preferred permeable material 42. The permeable material 41 is located on both sides below the retaining wall 3, and the preferred permeable material 42 is located on the upper side of the retaining wall 3 and the cement-clay composite sealing layer 2.

[0022] In this embodiment, the permeable material 41 and the preferred permeable material 42 are used. The permeable material is located on both sides of the retaining wall foundation, effectively enhancing the stability and drainage capacity of the foundation. The preferred permeable material 42 is located in the main area of ​​the retaining wall 3 and on top of the cement-clay composite sealing layer 2. With its excellent permeability, it forms an efficient main drainage channel. This design achieves complementary functions of "stabilizing the foundation at the bottom and rapidly draining at the top," significantly improving the overall stability and seepage prevention and drainage efficiency of the roadbed structure.

[0023] In some embodiments, the following steps are also included: The water-facing slope of the preferred permeable material 42 is sloped, filled, and leveled at a slope ratio of 1:1.75.

[0024] In this embodiment, the slope ratio of the water-facing side of the preferred permeable material 42 is set to 1:1.75. This slope ensures the long-term stability of the slope itself while providing sufficient working surface for the compaction machinery, which is conducive to obtaining a high and uniform compaction degree of the fill, thus ensuring the construction quality and inherent stability of the fill from the source.

[0025] In some embodiments, the following steps are also included: The gravel edging layer 5 is set to correspond to the slope of the water-facing side slope of the preferred permeable material 42.

[0026] In this embodiment, the gravel edging layer 5 is set to correspond to the slope ratio of the internal filling body, and the thickness is uniformly 1 meter, which ensures the uniformity of the protective section size and avoids local weak points.

[0027] In some embodiments, the thickness of the gravel edging layer 5 is 1 meter.

[0028] In this embodiment, constructing the gravel edging layer 5 to be 1m thick is sufficient to effectively perform the reverse filtration function, preventing the loss of internal fine particles, while providing a solid and flat base for the outer rigid slope protection, ensuring uniform stress and long-term stability of the slope protection structure. In some embodiments, the hexagonal block staggered joint masonry construction of the solid hexagonal block plus impermeable geotextile slope protection 6 is carried out.

[0029] In this embodiment, the staggered joint masonry allows the solid hexagonal blocks plus impermeable geotextile slope protection 6 to interlock and embed with each other, connecting the originally independent blocks into a more integrated grid structure, which greatly improves the overall rigidity and displacement resistance of the slope protection surface layer, and can more effectively resist external loads such as soil lateral pressure and water scouring force, preventing chain damage caused by local instability.

[0030] In some embodiments, the thickness of the cement-clay composite seal layer 2 is 1 meter.

[0031] In this embodiment, after the cement-clay composite sealing layer 2 is constructed to a thickness of 1 meter, the 1-meter thickness provides sufficient mass and volume for the composite sealing layer, enabling it to form a continuous, complete, and dense structural layer with a low permeability coefficient. This thickness effectively eliminates weak points caused by local unevenness or construction deviations, ensuring that its seepage prevention performance meets the long-term requirements of the project. Together with the underlying seepage-proof geotextile, it forms a solid and reliable "seepage barrier," maximizing the prevention of water infiltration into the underlying red sandy mudstone.

[0032] In some embodiments, obtaining a roadbed base that meets construction requirements specifically includes the following steps: Clean up the loose stones and crops on the original ground surface A, and remove the surface covering layer; After removing the overburden, steps are excavated within the cross-sectional area of ​​the roadbed; The exposed top surface of the red sandy mudstone layer after excavation was leveled and compacted to form a solid and flat roadbed base.

[0033] In this embodiment, by thoroughly cleaning the loose boulders and surface crops on the original ground and removing the surface covering layer, organic impurities, plant roots, and unstable deposits that may affect structural stability are effectively removed. Stepping treatment within the roadbed cross-section greatly increases the contact area and mechanical interlocking force between the newly constructed protective structure and the original foundation, effectively limiting the possibility of horizontal slippage at the interface between the old and new layers, thereby significantly enhancing the overall collaborative working ability between the protective structure and the underlying foundation. Special leveling and compaction treatment is applied to the top surface of the exposed red sandy mudstone layer after excavation, improving the initial bearing capacity and stiffness of the base, enabling it to uniformly support the upper impermeable layer and fill, and minimizing the risk of stress concentration or puncture of the impermeable layer due to uneven base. In addition, a water interception ditch E is provided above the original ground area A, a road slope B is provided below the original ground area A, and a roadside ditch F is provided below the road slope B.

[0034] On the other hand, see Figure 1 As shown, a protective structure for a red sandy mudstone roadbed saturated with water is provided, including an impermeable geotextile 1, which is laid on the roadbed base. A cement-clay composite sealing layer 2 is laid on the impermeable geotextile 1. A retaining wall 3 is provided on the side of the cement-clay composite sealing layer 2 near the bottom of the water body. A filling material 4 is provided in the area of ​​the retaining wall 3. A gravel edging layer 5 is laid on the side of the filling material 4. A solid hexagonal block plus impermeable geotextile slope protection 6 is laid on the outside of the gravel edging layer 5.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method adapted to the protection of red sandy mudstone subgrades from waterlogging, characterised in that, Includes the following steps: Obtain a roadbed base that meets construction requirements; A seepage-proof geotextile (1) is laid on the subgrade base, and a cement-clay composite sealing layer (2) is laid on the seepage-proof geotextile (1). Construct a retaining wall (3) on the side of the cement-clay composite seal layer (2) that is close to the bottom of the water body; Construction of filling material (4) is carried out in the area of ​​retaining wall (3); After the filling material is formed, the gravel edging layer (5) is constructed, and solid hexagonal blocks with impermeable geotextile are laid on the outside of the gravel edging layer (5) for slope protection (6). Complete the construction of roadbed protection.

2. A method of construction suitable for the protection of red sandy mudstone waterlogged embankments as claimed in claim 1 wherein, The filling material (4) includes a permeable material (41) and a preferred permeable material (42). The permeable material (41) is located on both sides below the retaining wall (3), and the preferred permeable material (42) is located on the upper side of the retaining wall (3) and the cement-clay composite seal layer (2).

3. A construction method for protecting red sandy mudstone subgrades exposed to water, as described in claim 2, characterized in that... It also includes the following steps: The water-facing slope of the preferred permeable material (42) is sloped, filled, and leveled at a slope ratio of 1:1.

75.

4. A construction method for protecting red sandy mudstone subgrades exposed to water, as described in claim 3, characterized in that... It also includes the following steps: The gravel edging layer (5) is set to correspond to the slope of the water-facing side slope of the preferred permeable material (42).

5. A construction method for protecting red sandy mudstone subgrades exposed to water, as described in claim 1, characterized in that... The thickness of the gravel edging layer (5) is 1 meter.

6. A construction method for protecting red sandy mudstone subgrades exposed to water, as described in claim 1, characterized in that, The construction of the hexagonal block staggered joint masonry of the solid hexagonal block with impermeable geotextile slope protection (6).

7. A construction method for protecting red sandy mudstone subgrades exposed to water, as described in claim 1, characterized in that, The thickness of the cement-clay composite seal layer (2) is 1 meter.

8. A construction method for protecting red sandy mudstone subgrades exposed to water, as described in claim 1, characterized in that, Obtaining a roadbed base that meets construction requirements specifically includes the following steps: The loose stones and ground crops on the original ground (A) were cleared, and the surface covering was removed; After removing the overburden, steps are excavated within the cross-sectional area of ​​the roadbed; The exposed top surface of the red sandy mudstone layer after excavation was leveled and compacted to form a solid and flat roadbed base.

9. A protective structure for water-saturated roadbeds made of red sandy mudstone, characterized in that, The system includes a geotextile (1), which is laid on the roadbed base. A cement-clay composite sealing layer (2) is laid on the geotextile (1). A retaining wall (3) is provided on the side of the cement-clay composite sealing layer (2) near the bottom of the water body. A filling material (4) is provided in the area of ​​the retaining wall (3). A gravel edging layer (5) is laid on the side of the filling material (4). A solid hexagonal block plus geotextile slope protection (6) is laid on the outside of the gravel edging layer (5).

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