Scouring protection structure for pier pile foundation

Abstract

The scouring protection structure for the pier pile foundation comprises a protection layer arranged around the pile foundation, and the protection layer comprises a sand filter layer covering a riverbed and a riprap layer covering the sand filter layer. The particle sizes of the rubble layer, the block stone layer and the accropode layer are gradually increased, and the rubble layer, the block stone layer and the accropode layer cover the sand filter layer from bottom to top layer by layer; a concrete layer is filled between the rubble layer and the block stone layer; the bridge pier pile foundation can be protected through the sand filtering layer covering the riverbed around the bridge pier pile foundation and the riprap layer covering the sand filtering layer, the sand filtering layer has the water-permeable and sand-impermeable performance, sand on the riverbed around the bridge pier pile foundation can be intercepted, the riprap layer can play a role of a cushion layer inverted filtering layer, and the riprap layer can also play a role of a riprap layer inverted filtering layer. Meanwhile, as a backfill material, the material plays a role in filling a scour pit; and the compaction pit is arranged, and the extension section of the protection layer is arranged on the protection slope, so that water flow impact in the water flow direction can be resisted in advance, and scattered sandy soil on the protection slope is reserved in the compaction pit.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge pier pile foundation protection, and in particular to a scour protection structure for bridge pier pile foundations. Background Art

[0002] Water damage to bridges has become the primary cause of bridge collapse and failure. It is sudden, destructive, and concealed, with high repair costs. Scour of pier pile foundations is one of the main causes of bridge water damage, and pier scour damage to bridges remains a common occurrence. Due to the influence of multiple factors such as tidal currents, wind and waves, and sediment rheology caused by dynamic loads from above, scour has become a widespread problem in pier pile foundations.

[0003] Traditionally, riprap technology has been used to protect bridge pile foundations from erosion by natural factors, such as water flow and wind and waves. However, this technology is ineffective. Stone barriers alone cannot effectively block erosion from these factors, leaving pile foundations vulnerable to damage. In particular, the large gaps between riprap stones allow water to penetrate these gaps and erode the riverbed. As erosion progresses, the riprap stones can sink and slide, causing the protective structure to fail and become less durable.

[0004] Therefore, it is necessary to improve the existing riprap protective structure layer to enhance its resistance to water erosion, prevent the riprap protective structure layer from being damaged, and effectively protect the pier pile foundation. Summary of the Invention

[0005] In view of this, the present invention provides a scour protection structure for bridge pier pile foundations, which can improve the resistance of the riprap protection structure layer to water erosion, prevent the riprap protection structure layer from being damaged, and effectively protect the bridge pier pile foundations.

[0006] The present invention can achieve the above problem through the following technical solutions:

[0007] A scour protection structure for a bridge pier pile foundation includes a protective layer arranged around the pile foundation, the protective layer including a sand filter layer covering the riverbed and a riprap layer covering the sand filter layer, the riprap layer including a crushed stone layer, a block stone layer and a twisted block layer with gradually increasing particle size covering the sand filter layer from bottom to top, and a concrete layer is filled between the crushed stone layer and the block stone layer.

[0008] Furthermore, it also includes a compaction pit set in the riverbed or seabed at the front end of the water-facing side of the pile foundation, and the end of the protective layer close to the compaction pit extends toward the compaction pit and is buried in the compaction pit to form an extension section.

[0009] Furthermore, the concrete layer is formed by laying bagged concrete on a crushed stone layer and has a thickness of not less than 20 cm.

[0010] Furthermore, the bag of the bagged concrete is made of woven fabric material and the concrete strength is C25.

[0011] Furthermore, the sand filter layer is laid on the riverbed using geotextiles, and the density of the geotextiles is not less than 350g / m 2 .

[0012] Furthermore, the crushed stone layer is set to be no less than 20 cm thick and the internal crushed stone particles have a diameter between 5 cm and 20 cm and are mixed and laid.

[0013] Furthermore, the block stone layer is set to be no less than 50 cm thick and the internal block stone particle size is between 20 cm and 50 cm and is mixed and laid.

[0014] Furthermore, the twisted blocks in the twisted block layer have a B-type structure and a thickness of not less than 100 cm.

[0015] Furthermore, the cross-section of the compaction pit along the direction of water erosion is an inverted trapezoid, and the waist of the trapezoid close to the pile foundation side forms a protective slope, and the extension section covers the protective slope and extends along the upper bottom of the trapezoid to cover the upper bottom of the trapezoid.

[0016] Furthermore, the protective slope is buried in a compaction pit by backfilling with natural sand, and the depth of the compaction pit is not less than 1.5 times the depth of wave erosion in the design period; the slope ratio of the protective slope is not greater than 1 / 3.

[0017] The beneficial effects of the present invention are as follows: the scour protection structure for bridge pier pile foundations of the present invention can protect the bridge pier pile foundations by means of a filter sand layer covering the riverbed around the bridge pier pile foundations and a riprap layer covering the filter sand layer. The filter sand layer is water-permeable but sand-impermeable, thereby trapping sand and soil on the riverbed around the bridge pier pile foundations. The riprap layer serves as both a cushioning and inverted filter layer and as backfill material to fill the scour pit. To prevent the loss of gravel in the gravel layer at the bottom of the riprap layer, the gravel layer is covered with bagged wet concrete mix, which is then bagged and dumped onto the top of the gravel layer. The wet concrete mix in the bags deforms by self-flowing according to the undulations of the terrain, densely covering the top of the bagged gravel. After the bagged concrete solidifies and hardens, it prevents surface scour, further preventing the loss of sand and soil around the pile foundations. The provision of a compaction pit and the arrangement of an extension of the protective layer on the protective slope can prevent the impact of water flow in the direction of the water flow in advance and retain sand and soil washed away from the protective slope in the compaction pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 Schematic diagram of the cross-sectional structure of the scour protection structure for the pier pile foundation according to the present invention;

[0020] Figure 2 Schematic diagram of the top view of the scour protection structure for pier pile foundations in the present invention;

[0021] The accompanying drawings are marked as follows: 1- riverbed; 2- pile foundation; 3- sand filter layer; 4- crushed stone layer; 5- concrete layer; 6- block stone layer; 7- twisted block layer; 8- extension section; 9- direction of water flow. DETAILED DESCRIPTION

[0022] As shown in the figure, the present invention provides a scour protection structure for a bridge pier pile foundation, including a protective layer arranged around the pile foundation 2, the protective layer including a sand filter layer 3 covering the riverbed 1 and a riprap layer covering the sand filter layer 3, the riprap layer including a crushed stone layer 4, a block stone layer 6 and a twisted block layer 7 with gradually increasing particle size and covering the sand filter layer 3 layer by layer from bottom to top, and a concrete layer 5 is filled between the crushed stone layer 4 and the block stone layer 6. The sand retention layer in this scheme includes a crushed stone layer 4, a block stone layer 6 and a twisted king-shaped block layer 7 which are gradually covered on the geotextile layer, and the particle size increases layer by layer. The crushed stone and the block stone are not mixed. Combined with the twisted king-shaped blocks, the strength is sufficient to resist the erosion of water flow, and the twisted king-shaped blocks can break the erosion direction of the water flow and dissipate the concentrated impact force of the water flow. Combined with the layered covering of the crushed stone layer 4 and the block stone layer 6, the integrity can be maintained, and the impact force of the water flow is consumed layer by layer, which can effectively prevent the erosion of the water flow and the loss of sand and gravel caused by the water flow; and water passes through the sand filter layer 3 without water accumulation and air accumulation, and natural sand and gravel, such as sand, mud, sand, soil, etc. are blocked by the covering structure of the sand filter layer 3, and cannot be carried away by water erosion. No sand and soil loss occurs when the water flow erodes, so that the bridge pier pile foundation 2 is effectively protected.

[0023] In this embodiment, the concrete layer 5 is formed by bagged concrete laid on the gravel layer 4, with a thickness of no less than 20 cm. The bags of bagged concrete are made of woven fabric and have a concrete strength of C25. The bagged concrete has a strength of C25 and solidifies underwater after dumping. The bagged concrete can be laid in multiple layers, up to a thickness of 1.5 m, to ensure complete coverage of the gravel layer 4. Each bag of bagged concrete weighs no less than 150 kg and is made of woven fabric. To prevent the loss of gravel from the gravel layer 4 at the bottom of the dumping layer, bagged concrete is placed over the gravel layer 4. After bagging, the concrete is dumped onto the top of the gravel layer 4. The bagged concrete deforms according to the terrain, densely covering the top of the gravel layer. After solidification, the bagged concrete prevents surface erosion, further preventing the loss of sand and soil around the pile foundation 2. Furthermore, the bagged concrete is flexible during dumping, without sharp edges, and is protected by a woven bag. When it falls onto the pile foundation 2, it deforms, effectively protecting the pile foundation 2 from damage.

[0024] In this embodiment, the sand filter layer 3 is laid on the riverbed 1 using geotextile, and the density of the geotextile is not less than 350g / m2 The geotextile has high water permeability. When water flows through, the sand is intercepted, which can diffuse the concentrated stress of the upper layer and prevent the mixing of the lower sand and the upper stone. Combined with the filter sand layer, the sand is intercepted, and the sand is not lost or lost less when the water erodes. The bridge pier pile foundation 2 is effectively protected, and the degree of erosion caused by the impact of the water flow is reduced, playing a role in protecting the bridge pier pile foundation 2. The density of the geotextile is not less than 350g / m 2 , further geotextile density is 350g / m 2 ~500g / m 2 In this scheme, the density of geotextile is 350g / m 2 .

[0025] In this embodiment, the crushed stone layer 4 is not less than 20cm thick and the crushed stone particle size is between 5cm and 20cm. The crushed stone layer 4 is 20cm thick and the crushed stone particle size is less than 20cm. The relative compaction density Dr of the crushed stone layer 4 is ≥ 0.6, and the relative compaction density of the crushed stone layer 4 is between 0.6 and 0.9. The saturated compressive strength of the crushed stone layer 4 is not less than 30Mpa, and the saturated compressive strength of the crushed stone layer 4 is between 30Mpa and 50Mpa. The mud content of the crushed stone layer 405 is less than 10%, and the mud content of the crushed stone layer 4 is between 5% and 10%. In this solution, the crushed stone layer 4 is 20cm thick and the crushed stone particle size is less than 20cm. Stone particles with a diameter of 5 cm to 20 cm are mixed and laid so that the relative compaction density, saturated compressive strength and mud content of the crushed stone layer 4 are adjusted to meet the above standards. During actual construction, the crushed stone particle size is adjusted according to the thickness of the crushed stone layer 4. For example, when the thickness of the crushed stone layer 4 is 30 cm, the crushed stone particle size that can be used is between 10 cm and 30 cm. The relative compaction density, saturated compressive strength and mud content of the crushed stone layer 4 are adjusted according to the degree of erosion by waves and construction conditions to achieve the expected effect of resisting water erosion and intercepting small and medium-sized sediment as expected by this scheme. No further details are given here.

[0026] In this embodiment, the thickness of the block stone layer 6 is not less than 50cm and the internal block stone particle size is between 20cm and 50cm. The porosity of the block stone layer 6 is not more than 28%, and the porosity of the further block stone layer 6 is between 5% and 28%; the saturated compressive strength of the block stone layer 6 is not less than 30Mpa, and the saturated compressive strength of the further block stone layer 6 is between 30Mpa and 50Mpa; the mud content of the block stone layer 6 is less than 10%, and the mud content of the further block stone layer 6 is between 5% and 10%; in this solution, the thickness of the block stone layer 6 is 50cm, and the crushed stone particle size is between 20cm and 50cm, so as to adjust the porosity of the block stone layer 6 and the saturated compressive strength of the block stone layer 6. The strength and mud content of the stone layer 6 meet the above standards. During actual construction, the particle size of the large crushed stones is adjusted according to the thickness of the stone layer 6. For example, when the thickness of the stone layer 6 is 100 cm, the stone particles with a particle size of 50 cm to 100 cm can be mixed and laid. The porosity of the stone layer 6, the saturated compressive strength of the stone layer 6, and the mud content of the stone layer 6 are adjusted according to the degree of erosion by the waves and the construction conditions to achieve the expected effect of resisting the water flow and intercepting large-grained sand and gravel in this solution. I will not go into details here.

[0027] In this embodiment, the twisted blocks in the twisted block layer 7 are of B-type structure and have a thickness of not less than 100 cm; further, the thickness of the twisted blocks is between 100 cm and 120 cm, and the number of twisted blocks per 100 square meters of protective area is not less than 150. Further, the number of twisted blocks per 100 square meters of protective area is between 150 and 250. In this solution, the thickness of the twisted blocks is 100 cm, and the number of twisted blocks per 100 square meters of protective area is approximately 150. The twisted blocks are closely arranged, and the laying direction of the twisted blocks is random. More specifically, it is necessary to ensure that the two support rods in each twisted block touch the ground at the same time, are placed randomly at fixed points, and are placed obliquely on the slope. The placement directions of adjacent blocks are different, and artificial support is used during the hoisting process to ensure that two support rods in the block touch the ground at the same time, thereby weakening the impact force of the waves and protecting the breakwater.

[0028] In this embodiment, it also includes a compaction pit arranged in the riverbed 1 or the seabed at the front end of the water-facing side of the pile foundation 2, and the protective layer extends toward the compaction pit near the end of the compaction pit and is buried in the compaction pit to form an extension section 8; the cross-section of the compaction pit along the direction of water erosion is an inverted trapezoid, and the waist of the trapezoid near the side of the pile foundation 2 forms a protective slope, and the extension section 8 covers the protective slope and extends along the upper bottom of the trapezoid to cover the upper bottom of the trapezoid; the protective slope is buried in the compaction pit by backfilling with natural sand and soil, and the depth H of the compaction pit is not less than 1.5 times the design life wave erosion depth; the slope ratio of the protective slope is not greater than 1 / 3.

[0029] As shown in the figure, the extension section 8 covers the protective slope and continues along the lower floor of the compaction pit, covering the bottom surface of the compaction pit. The inverted trapezoidal structure of the compaction pit further enhances the protection against water flow and stabilizes sand and gravel. It can guide the direction of water flow, reduce the impact of erosion, and improve the protection effect. In this solution, the depth of the compaction pit is designed to be 1.5 times the design life water erosion depth. Since the slope ratio of the protective slope is no more than 1 / 3, the slope ratio of the protective slope is further adjusted to be between 1 / 3 and 1 / 4, with the slope ratio of 1 / 3 in this solution. To ensure the impact stability of the protective layer, the slope ratio of the protective slope of the compaction pit is no more than 1 / 3, and the upper part is backfilled with natural sand, integrating the compaction pit structure with the riverbed 1 and improving the protection effect. The compaction pit and the extension section 8 of the protective layer on the protective slope can prevent the impact of water flow from the direction 9 and retain sand and soil washed away from the protective slope within the compaction pit.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A scour protection structure for a bridge pier pile foundation, characterized by: It includes a protective layer arranged around the pile foundation, the protective layer includes a sand filter layer covering the riverbed and a riprap layer covering the sand filter layer, the riprap layer includes a crushed stone layer, a block stone layer and a twisted block layer with gradually increasing particle size covering the sand filter layer from bottom to top, and a concrete layer is filled between the crushed stone layer and the block stone layer.

2. The scour protection structure for a bridge pier pile foundation according to claim 1, characterized in that: It also includes a compaction pit arranged in the riverbed or seabed at the front end of the water-facing side of the pile foundation, and the end of the protective layer close to the compaction pit extends toward the compaction pit and is buried in the compaction pit to form an extension section.

3. The scour protection structure for a bridge pier pile foundation according to claim 1, characterized in that: The concrete layer is formed by laying bagged concrete on a crushed stone layer and has a thickness of not less than 20 cm.

4. The scour protection structure for a bridge pier pile foundation according to claim 3, characterized in that: The bag of the bagged concrete is made of woven cloth and the concrete strength is C25.

5. The scour protection structure for a bridge pier pile foundation according to claim 1, characterized in that: The sand filter layer is laid on the riverbed with geotextile, and the density of the geotextile is not less than 350g / m 2 .

6. The scour protection structure for a bridge pier pile foundation according to claim 1, characterized in that: The thickness of the crushed stone layer is not less than 20 cm and the internal crushed stone particle size is between 5 cm and 20 cm and is mixed and laid.

7. The scour protection structure for a bridge pier pile foundation according to claim 1, characterized in that: The block stone layer is set to be no less than 50 cm thick and the internal block stone particle size is between 20 cm and 50 cm and is mixed and laid.

8. The scour protection structure for a bridge pier pile foundation according to claim 1, characterized in that: The twisted blocks in the twisted block layer have a B-type structure and a thickness of not less than 100 cm.

9. The scour protection structure for a bridge pier pile foundation according to claim 2, characterized in that: The cross section of the compaction pit along the direction of water erosion is in an inverted trapezoidal shape, and the waist of the trapezoid close to the pile foundation side forms a protective slope. The extension section covers the protective slope and extends along the upper bottom of the trapezoid to cover the upper bottom of the trapezoid.

10. The scour protection structure for a bridge pier pile foundation according to claim 9, characterized in that: The protective slope is buried in a compaction pit by backfilling with natural sand, and the depth of the compaction pit is not less than 1.5 times the depth of wave erosion in the design period; the slope ratio of the protective slope is not greater than 1 / 3.

Images