Dam body structure suitable for aeolian sand area

Abstract

The dam body structure suitable for the aeolian sand area comprises a dam body, a dam crest, an upstream side dam, a downstream side dam and a pile foundation, the dam body is a dispersive soil material area, a modified dispersive soil material area is arranged on the surface of the dam body, the upstream side dam comprises an anti-seepage structure, and the downstream side dam is provided with a downstream protection slope; a concrete tooth wall is arranged at the bottom of the upstream side dam, a wave wall is arranged at the top of the upstream side dam, a mattress drainage body and an arris drainage body are arranged at the bottom of the downstream side dam and connected with each other, inverted filter layers are arranged between the mattress drainage body and the dispersive soil material area and between the arris drainage body and the dispersive soil material area, and seepage stopping grooves are formed in the pile foundation along the axis of the dam body. The modified dispersive soil materials are arranged on the periphery of the dispersive soil material area of the dam body so as to protect the dispersive soil materials, the crack is sealed through the anti-seepage structure so as to perform anti-seepage treatment on the upstream, and the inverted filter layer is arranged so as to achieve the functions of inverted filtration and drainage. The inverted filter layer is compact and hard in texture, resistant to weather, continuous in grain composition and good in drainage performance and permeation stability.

Description

Technical Field

[0001] The utility model belongs to the technical field of water conservancy engineering design, and in particular relates to a dam body structure suitable for aeolian sand areas. Background Art

[0002] When constructing water conservancy projects in areas where desert aeolian sand is widely distributed, it is necessary to study the deformation, uneven settlement, leakage, and infiltration stability of the dam foundation; it is necessary to study the characteristics, utilization, and filling standards of desert aeolian sand; it is necessary to identify earthquake liquefaction and determine the acceptance standards for foundation treatment.

[0003] Dispersive soil is easily eroded by water. When this soil encounters water with low salt concentration, the soil particles on the surface of the soil body gradually fall off one by one and become a suspension. If it encounters flowing water, the dispersed soil material will be taken away, and the erosion phenomenon is even more serious than fine sand or silt. The position of dispersed soil on the plasticity diagram is above line A, between loess and expansive soil, and a small part overlaps with loess. It is clay soil, and the distribution range is from low liquid limit clay (CL) to medium liquid limit clay (CI), and some are high liquid limit clay (CH). The main reason for dispersion is that the repulsion between soil particles exceeds the suction force. There are more sodium ions in the soil material, and it has a higher exchangeable sodium percentage (ESP), which makes the water film around the soil particles thicker and reduces the suction between soil particles. Once it comes into contact with water with low salt concentration, the particles on the surface of the soil body gradually fall off one by one and become a suspension. If it is flowing water, the particles will be lost with the water. The lower the content of water-soluble salt and soluble salt contained in the reservoir water, the greater the possibility of pipe burst.

[0004] The dispersibility mechanism of dispersible clay can be explained from the different mineral components and microstructure of clay.

[0005] The basic structural units of clay minerals are silicon-oxygen tetrahedron and aluminum-oxygen octahedron. Montmorillonite is a 2:1 type clay mineral with a three-layer structure. Its structural unit is composed of two silicon-oxygen tetrahedrons with an aluminum-oxygen octahedron sandwiched between them. Its characteristic is that the two layers are connected by oxygen atoms and oxygen atoms through the intermolecular interaction force (Van der Bi force). The interlayer connection is extremely weak, and water molecules can freely enter the interlayer, showing the characteristics of water absorption, expansion or dispersion. The structural unit of illite is the same as that of montmorillonite, but the crystal layers are connected by potassium ions, and its stability is better than that of montmorillonite. There is also isomorphous substitution inside the illite lattice. For example, 1 / 6 of silicon (Si) in the silicon-oxygen tetrahedron can be replaced by aluminum (Al), making the unit cell negatively charged. Illite undergoes isomorphous substitution and becomes montmorillonite after potassium removal. Therefore, illite also has the characteristics of expansion and dispersion.

[0006] Since the elements in montmorillonite crystals often undergo isomorphous substitution, the unit cell produces excess negative charge due to the replacement of high-valent ions by low-valent ions. This excess negative charge needs to adsorb cations, usually calcium (Ca 2+ ) or sodium (Na+ ) ions to balance, when the adsorption of sodium ions is more, it is called sodium montmorillonite, which is a dispersed soil, which continues to expand until it is dispersed into extremely thin single crystal cells. At this point, the soil has been seriously dispersed.

[0007] Therefore, some necessary engineering measures need to be adopted to ensure the normal operation of the earth-rock dam. Utility Model Content

[0008] The purpose of the utility model is to provide a dam body structure suitable for aeolian sand areas, so as to overcome the above-mentioned technical problems in the prior art.

[0009] To this end, the technical solution provided by the utility model is as follows:

[0010] A dam structure suitable for aeolian sand areas, comprising a dam body, a dam top, an upstream side dam, a downstream side dam and a pile foundation, wherein the dam body is arranged on the pile foundation, the dam body is a dispersed soil material area, a modified dispersed soil material area is arranged on the surface of the dispersed soil material area, the upstream side dam comprises an anti-seepage structure, and the downstream side dam is provided with a downstream slope protection;

[0011] A concrete tooth wall is provided at the bottom of the upstream dam, a wave-breaking wall and a geotextile are provided at the top of the dam, a mattress drainage body and a prism drainage body are provided at the bottom of the downstream dam from the inside to the outside, the mattress drainage body is connected to the prism drainage body, and an anti-filtration layer is provided between the mattress drainage body and the prism drainage body and the dispersed soil area of ​​the dam body, and a seepage cut-off groove is arranged on the pile foundation along the axis of the dam body.

[0012] The anti-seepage structure is composed of a concrete prefabricated block, a cushion layer and a composite geomembrane from top to bottom. The two ends of the composite geomembrane are respectively fixed on the wave-breaking wall base and the concrete tooth wall. The concrete prefabricated block is in the shape of a hexagonal body, and the cushion layer is coarse sand.

[0013] The modified dispersed soil material area includes an upstream modified dispersed soil material area, a dam bottom modified dispersed soil material area and a downstream modified dispersed soil material area;

[0014] The downstream modified dispersed soil material area is arranged at the bottom of the downstream slope protection, and the upstream modified dispersed soil material area is arranged at the bottom of the anti-seepage structure.

[0015] The top of the composite geomembrane is anchored on the side wall of the wave-breaking wall, and the bottom of the composite geomembrane is anchored in the concrete tooth wall.

[0016] The modified dispersed soil material zone is prepared by mixing dispersed soil with quicklime, slaked lime or aluminum sulfate, with a weight ratio of (10-1):1.

[0017] The top elevation of the prism drainage body is 0.5m-1.5m higher than the highest water level downstream.

[0018] The filter layer is composed of a sand layer with a thickness of 18-22 cm and a crushed stone layer with a thickness of 28-32 cm.

[0019] The beneficial effects of the utility model are:

[0020] The utility model provides a dam structure suitable for wind-blown sand areas. The modified dispersed soil material is arranged around the dispersed soil material area of ​​the dam body to protect the dispersed soil material, and the cracks are closed by the anti-seepage structure to carry out anti-seepage treatment on the upstream. An anti-filter layer is arranged between the mattress drainage body and the prism drainage body and the dispersed soil material area of ​​the dam body to achieve anti-filtration and drainage. The anti-filter layer has a dense texture, is hard, and is resistant to weathering, has continuous particle grading, and has good drainage and permeability stability.

[0021] The dam structure, which is suitable for wind-blown sand areas, adopts concrete tooth walls to prevent the composite geomembrane, cushion layer and upstream slope protection (concrete prefabricated blocks) from moving upstream. The pile foundation uses bedrock as the bearing layer at the pile end, which has a large thickness, stable layer position, continuous distribution, and high bearing capacity. The depth of the pile end entering the bearing layer should be 1.0 to 2.0 m. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of an implementation method of the utility model.

[0023] In the figure: 1. wave-breaking wall; 2. geotextile; 3. upstream modified dispersed soil area; 4. composite geomembrane; 5. cushion layer; 6. concrete precast blocks; 7. concrete tooth wall; 8. downstream modified dispersed soil area; 9. dispersed soil area; 10. modified dispersed soil area at the dam bottom; 11. pile foundation; 12. seepage cut-off trough; 13. mattress drainage body; 14. prism drainage body; 15. downstream slope protection; 16. filter layer. DETAILED DESCRIPTION

[0024] The following is an explanation of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0025] The exemplary embodiments of the present invention are now introduced with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0026] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0027] Example 1

[0028] The utility model provides a dam structure suitable for wind-blown sand areas, such as Figure 1 As shown, it includes a dam body, a dam top, an upstream side dam, a downstream side dam and a pile foundation 11, the dam body is arranged on the pile foundation 11, the dam body is a dispersed soil material area 9, the surface of the dispersed soil material area 9 is provided with a modified dispersed soil material area, the upstream side dam includes an anti-seepage structure, and the downstream side dam is provided with a downstream slope protection 15;

[0029] A concrete tooth wall 7 is provided at the bottom of the upstream dam, a wave-breaking wall 1 and a geotextile 2 are provided at the top of the dam, a mattress drainage body 13 and a prism drainage body 14 are provided at the bottom of the downstream dam from the inside to the outside, the mattress drainage body 13 is connected to the prism drainage body 14, and an anti-filtration layer 16 is provided between the mattress drainage body 13 and the prism drainage body 14 and the dispersed soil area 9 of the dam body, and a seepage cut-off groove 12 is arranged on the pile foundation 11 along the axis of the dam body.

[0030] The dam body is a quadrilateral filled with dispersed soil (i.e. dispersed soil area 9). The geotextile 2 is a geosynthetic material with anti-seepage function. The unit area mass of the geotextile 2 is not less than 300g / m 2 .

[0031] The dam structure provided by the utility model is suitable for wind-blown sand areas. The modified dispersed soil material is arranged around the dispersed soil material area 9 of the dam body to protect the dispersed soil material, and the cracks are closed by the anti-seepage structure to perform anti-seepage treatment on the upstream. An anti-filter layer 16 is arranged between the mattress drainage body 13 and the prism drainage body 14 and the dispersed soil material area 9 of the dam body to achieve anti-filtration and drainage. The anti-filter layer 16 has a dense texture, is hard, and is resistant to weathering, has continuous particle grading, and has good drainage and permeability stability.

[0032] Example 2

[0033] On the basis of Example 1, this embodiment provides a dam structure suitable for aeolian sand areas, wherein the anti-seepage structure includes a precast concrete block 6, a cushion layer 5 and a composite geomembrane 4 arranged in sequence from top to bottom, and the two ends of the composite geomembrane 4 are respectively fixed on the base of the wave-breaking wall 1 and the concrete tooth wall 7, the precast concrete block 6 is 12-16 cm thick and is hexagonal in shape, and the cushion layer 5 is coarse sand with a thickness of 28-32 cm.

[0034] The prefabricated concrete block 6 is used for upstream slope protection, and the unit area mass of the composite geomembrane 4 is 350g / m 2 .like Figure 1 As shown, the dam height is h3, the downstream elevation is h2, the top elevation of the prism drainage body 14 is h1, and a 3m wide horseway is set at the downstream elevation h2. The area from h3 to the dam top elevation is turf slope protection, and the area below h3 is the prism drainage body 14, which adopts dry masonry stone slope protection. The remaining slopes are protected by turf planted in C25F300 concrete arches. The arch size is 5m×6m and the thickness is 0.3m.

[0035] Example 3

[0036] On the basis of Example 1, this embodiment provides a dam structure suitable for aeolian sand areas, wherein the modified dispersed soil material area includes an upstream modified dispersed soil material area 3, a dam bottom modified dispersed soil material area 10 and a downstream modified dispersed soil material area 8;

[0037] The downstream modified dispersed soil material area 8 is arranged at the bottom of the downstream slope protection 15, and the upstream modified dispersed soil material area 3 is arranged at the bottom of the anti-seepage structure.

[0038] The thickness of the modified dispersed soil in the upstream modified dispersed soil area 3, the dam bottom modified dispersed soil area 10 and the downstream modified dispersed soil area 8 shall not be less than 3.0m, and the filling compaction degree shall not be less than 98%.

[0039] Example 4

[0040] On the basis of Example 2, this example provides a dam structure suitable for aeolian sand areas, wherein the top of the composite geomembrane 4 is anchored to the side wall of the wave-breaking wall 1 , and the bottom of the composite geomembrane 4 is anchored in the concrete tooth wall 7 .

[0041] The concrete tooth wall 7 can prevent the composite geomembrane 4, cushion layer 5 and upstream slope protection (concrete prefabricated block 6) from moving upstream.

[0042] Example 5

[0043] Based on Example 1, this example provides a dam structure suitable for aeolian sand areas, wherein the modified dispersed soil material area is prepared by mixing dispersed soil with quicklime, slaked lime or aluminum sulfate, with a weight ratio of (10-1):1.

[0044] The earth-rock dam can also operate normally after the dispersed soil is modified by slaked lime or alum (aluminum sulfate) solution.

[0045] Among them, the dispersed soil materials mainly include excavated materials from dam foundations, bank slopes and other parts. The excavated materials in dispersed soil material area 9 have a clay content of 10% to 30%, a plasticity index of 7-17, an organic matter content of no more than 5%, a water-molten salt content of no more than 3%, and a permeability coefficient of no more than 1×10 -4 cm / s, and the compaction degree is not less than 98%.

[0046] Example 6

[0047] On the basis of Example 1, this example provides a dam structure suitable for aeolian sand areas, wherein the top elevation of the prism drainage body 14 is 0.5m-1.5m higher than the highest downstream water level.

[0048] The filter layer 16 is composed of a sand layer with a thickness of 18-22 cm and a crushed stone layer with a thickness of 28-32 cm.

[0049] The thickness of the 16th filter layer shall not be less than 46cm. The filter material shall be dense, hard, resistant to weathering, with continuous particle gradation, the maximum particle size shall not exceed 75mm, and the content of particles less than 0.075mm shall not exceed 5%. The relative density of the filter material shall not be less than 0.70, and the dry density shall not be less than 22kN / m 3 , and has good drainage and penetration stability.

[0050] In the utility model, the pile foundation 11 uses bedrock as the bearing layer at the pile end. The layer is required to be stable, continuously distributed, and have a high bearing capacity. The depth of the pile end entering the bearing layer is preferably 1.0 to 2.0 m. The pile foundation 11 can be cast with concrete not less than C30. The cast-in-place pile foundation 11 extends into the lower limit layer of the riverbed bedrock with strong differentiation. The depth of the cast-in-place pile is not less than 50 m, and the minimum spacing of the cast-in-place piles is not less than 2 times the pile diameter. The pile foundation 11 can be treated with lime soil compaction piles. The row spacing (direction of the dam axis) of the pile foundation 11 is not more than 3 m, and the spacing (vertical to the dam axis) is not more than 3 m. The treatment depth is preferably 3 to 15 m. The protection range of the pile foundation 11, the distance between the upstream and downstream and the dam axis is not less than 0.5 times the dam height, and the distance between the left and right banks and the center line of the dam is not less than 0.5 times the dam height.

[0051] The cut-off trench 12 is cleared to the lower limit of strong weathering of the rock, and a joint groove is excavated at the axis of the dam, with a slope ratio of 1:1.0 on both sides. The cross section of the cut-off trench 12 is an inverted trapezoid, and the bottom width is not less than the width of the dam top. The cut-off trench 12 needs to be backfilled and compacted with high plastic soil.

[0052] The composite geomembrane 4 is anchored to the base of the wave-breaking wall 1 by rivets. The mattress drainage body 13 is located at the bottom of the dam body and is built with stone blocks. From the inside to the outside, a 20 cm thick sand filter, a 30 cm thick gravel filter, a 100 cm block horizontal drainage layer, a 30 cm thick gravel filter, and a 20 cm thick sand filter are arranged in sequence. The top width of the drainage prism is 3m. The upstream of the mattress drainage is connected to the composite geomembrane 4, and the downstream is connected to the prism drainage body 14. The filter layer 16 is arranged at the junction of the drainage prism and the dam body soil. The filter layer 16 is composed of a 20 cm thick sand layer and a 30 cm thick gravel. The stone filling standards of the mattress drainage body 13 and the prism drainage body 14 are: porosity 19-26%, permeability coefficient greater than 1×10 -2 cm / s, and the content of particles with a diameter less than 0.075 mm does not exceed 5%.

[0053] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are identical or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A dam structure suitable for wind-blown sand areas, characterized by: The dam comprises a dam body, a dam top, an upstream side dam, a downstream side dam and a pile foundation, wherein the dam body is arranged on the pile foundation, the dam body is a dispersed soil material area, the surface of the dispersed soil material area is provided with a modified dispersed soil material area, the upstream side dam comprises an anti-seepage structure, and the downstream side dam is provided with a downstream slope protection; A concrete tooth wall is provided at the bottom of the upstream dam, a wave-breaking wall and a geotextile are provided at the top of the dam, a mattress drainage body and a prism drainage body are provided at the bottom of the downstream dam from the inside to the outside, the mattress drainage body is connected to the prism drainage body, and an anti-filtration layer is provided between the mattress drainage body and the prism drainage body and the dispersed soil area of ​​the dam body, and a seepage cut-off groove is arranged on the pile foundation along the axis of the dam body.

2. A dam structure suitable for wind-blown sand areas according to claim 1, characterized in that: The anti-seepage structure is composed of a concrete prefabricated block, a cushion layer and a composite geomembrane from top to bottom. The two ends of the composite geomembrane are respectively fixed on the wave-breaking wall base and the concrete tooth wall. The concrete prefabricated block is in the shape of a hexagonal body, and the cushion layer is coarse sand.

3. The dam structure suitable for wind-blown sand areas according to claim 1, characterized in that: The modified dispersed soil material area includes an upstream modified dispersed soil material area, a dam bottom modified dispersed soil material area and a downstream modified dispersed soil material area; The downstream modified dispersed soil material area is arranged at the bottom of the downstream slope protection, and the upstream modified dispersed soil material area is arranged at the bottom of the anti-seepage structure.

4. The dam structure suitable for wind-blown sand areas according to claim 2, characterized in that: The top of the composite geomembrane is anchored on the side wall of the wave-breaking wall, and the bottom of the composite geomembrane is anchored in the concrete tooth wall.

5. A dam structure suitable for aeolian sand areas according to any one of claims 1 to 4, characterized in that: The top elevation of the prism drainage body is 0.5m-1.5m higher than the highest water level downstream.

6. A dam structure suitable for aeolian sand areas according to any one of claims 1 to 4, characterized in that: The filter layer is composed of a sand layer with a thickness of 18-22 cm and a crushed stone layer with a thickness of 28-32 cm.

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