Foundation structure of closed red mud reservoir drainage open channel

Abstract

The utility model discloses a foundation structure of a closed drainage open channel of a red mud reservoir, which is constructed by an ash water absorption layer (3), a gravel foundation layer (4), a lower geogrid (8-1), a lower gravel foundation layer (5), an upper geogrid (8-2), an upper gravel foundation layer (6) and a silty clay cushion layer (7) which are sequentially backfilled and paved from bottom to top on a red mud lower digging line (1), and the ash water absorption layer (3), the gravel foundation layer (4), the lower geogrid (8-1), the lower gravel foundation layer (5), the upper geogrid (8-2), the upper gravel foundation layer (6) and the silty clay cushion layer (7) are arranged on the red mud lower digging line (1). According to the utility model, the problems of poor water permeability and low bearing capacity of red mud in a central area are solved, and the foundation stability is improved from an integral structure; the problem of uneven foundation collapse caused by difficult drainage after gravel compaction of the fine-grained red mud is solved, and the safety and stability of a construction working face are guaranteed; the bearing capacity of the foundation is improved, meanwhile, the foundation treatment range is reduced, resource waste caused by single soil covering and gravel compaction is avoided, and investment is saved.

Description

Technical Field

[0001] The utility model belongs to the technical field of mine tailings pond closure and management, and specifically relates to the construction of a red mud pond closure drainage open channel foundation structure. Background Art

[0002] As one of the major sources of danger in mines, tailings ponds still need a complete drainage system for flood discharge in the reservoir area after closure. Most of them adopt an open drainage channel structure after closure. The slope of the reservoir surface is adjusted by covering with soil, and rainwater flows into the open drainage channel and then discharges out of the reservoir through the open drainage channel.

[0003] Due to the tail discharge operation, the red mud in the red mud reservoir has an obvious stratified and zoned deposition pattern, which is roughly manifested as coarse-grained red mud deposited in front of the dam, and fine-grained red mud deposited in the center and the back area. The foundation treatment of fine-grained red mud is a prerequisite for the construction of drainage facilities, especially for the surrounding dam. The fine-grained red mud in the central area has poor permeability and large accumulation thickness, and the problem of soft foundation is more prominent. Traditional methods of crushed stone compaction and covering cannot achieve good results in specific areas, resulting in waste of resources and economy. Therefore, the soft foundation treatment of the open drainage channel of the red mud reservoir is an issue that cannot be ignored in closed reservoirs. Summary of the invention

[0004] The purpose of the utility model is to provide a basic structure of a closed drainage open channel for a red mud reservoir in view of the above-mentioned problems existing in the prior art.

[0005] In order to achieve the above-mentioned purpose of the utility model, the utility model adopts the following technical solutions for the foundation structure of a closed drainage open channel of a red mud reservoir:

[0006] The utility model discloses a foundation structure of a red mud reservoir closed reservoir drainage open channel. A red mud undercut line is arranged at the red mud position of the proposed drainage open channel. The characteristic is that the designed foundation structure is constructed by backfilling and laying an ash slag water absorption layer, a sand and gravel foundation layer, a lower geogrid, a lower crushed stone foundation layer, an upper geogrid, an upper crushed stone foundation layer, and a silty clay cushion layer from bottom to top on the red mud undercut line. The ash slag in the ash slag water absorption layer is used to neutralize the moisture of red mud particles; the sand and gravel are used to improve the bearing capacity of the foundation and ensure uniform stress on the foundation; the geogrid and the crushed stone foundation layer are used to improve the bearing capacity of the foundation, and the silty clay cushion layer is used to adjust the surface to reach the level of the top surface of the foundation, so as to ensure the construction quality of the upper drainage open channel.

[0007] Furthermore, the thickness h1 of the ash water absorption layer is 40 to 65 cm; the thickness h2 of the sandstone foundation layer is 40 to 65 cm, the thickness h3 of the lower crushed stone foundation layer is 30 to 50 cm, the thickness h4 of the upper crushed stone foundation layer is 30 to 50 cm, and the thickness h5 of the silty clay cushion layer is 20 to 40 cm.

[0008] Furthermore, the size of the slabs used in the slab sandstone foundation layer is L=20-40cm in one direction, and the thickness of the middle part is not less than 15cm. The slabs are filled with sandstone in the gaps of the slabs, and the mass of the filled sandstone particles with a particle size greater than 0.5mm accounts for more than 50% of the total mass, the clay content is less than 2%, and the maximum particle size does not exceed 2mm. The slab sandstone is used to improve the bearing capacity of the foundation and ensure that the foundation is evenly stressed, and the crushed stone is required to be hard and corrosion-resistant.

[0009] As a preferred embodiment of the present invention, the thickness of the ash water absorption layer h1 is 40 cm to 60 cm; the thickness of the sandstone base layer h2 is 40 to 60 cm.

[0010] As a preferred embodiment of the present invention, the thickness h3 of the lower crushed stone foundation layer is 35 cm to 45 cm, and the thickness h4 of the upper crushed stone foundation layer is 35 cm to 45 cm.

[0011] As a preferred embodiment of the present invention, the thickness h5 of the silty clay cushion is 25 to 36 cm. The silty clay cushion requires good material gradation, and the silty clay cushion is used to adjust the surface to reach the level of the top surface of the foundation to ensure the construction quality of the upper drainage open channel.

[0012] As a preferred embodiment of the present invention, the model of the lower geogrid and the upper geogrid is EGA100*100.

[0013] The utility model has the following positive effects after the foundation structure of the red mud reservoir closed drainage open channel adopts the above technical scheme:

[0014] (1) The problem of poor permeability and low bearing capacity of red mud in the central area was solved, and the foundation stability was improved from the perspective of the overall structure;

[0015] (2) It solved the problem of uneven foundation collapse caused by drainage difficulties after fine-grained red mud was compacted by crushed stone, ensuring the safety and stability of the construction surface;

[0016] (3) While improving the bearing capacity of the foundation, it reduces the scope of foundation treatment, avoids the waste of resources caused by single covering soil and crushed stone compaction, and saves investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The utility model is a schematic cross-sectional view of the foundation structure of a closed drainage open channel of a red mud reservoir.

[0018] Figure numerals: 1-red mud excavation line; 2-red mud; 3-ash water absorption layer; 4-sand and gravel foundation layer; 5-lower crushed stone foundation layer; 6-upper crushed stone foundation layer; 7-silty clay cushion layer; 8-1-lower geogrid; 8-2-upper geogrid; 9-open drainage channel. DETAILED DESCRIPTION

[0019] To further describe the present invention, the basic structure of a closed drainage open channel for a red mud reservoir of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0020] In the embodiment, after a certain four-sided dammed red mud reservoir was stopped to discharge, drainage research was carried out on the red mud in the reservoir. The results showed that the drainage methods such as radiation well drainage and electrode drainage were not effective, the water output was small, and the bound water between red mud particles was difficult to discharge. The closed reservoir drainage system was designed as an open drainage channel. The foundation treatment of the open drainage channel first adopted traditional crushed stone compaction. During the crushed stone compaction process, the foundation treatment had problems such as large depth, wide range and large settlement.

[0021] Depend on Figure 1 As shown in the cross-sectional schematic diagram of the foundation structure of the red mud reservoir closed drainage open channel of the utility model, in order to solve the above problems, the foundation structure of the red mud reservoir closed drainage open channel of the utility model is implemented by the following steps:

[0022] S1: Soft foundation excavation of drainage open channel - neutralization of red mud moisture

[0023] First, dig the red mud 2 down to the red mud digging line 1 with a designed depth of h at the location of the planned red mud reservoir closed drainage open channel, and the digging width b = 1.3h. After digging, dry it for 2 days to evaporate the surface moisture of the red mud 2. After the surface red mud of the red mud digging line 1 is dried, lay the ash water absorption layer 3 with a backfill thickness of h1 of 50cm. The ash particles in the ash water absorption layer 3 have a particle size of d1 = 0.1-0.5mm and a mass proportion of not less than 50% of the total mass. The particles are dried and then rolled 3-5 times with a small machine to neutralize the moisture in the red mud.

[0024] S2: Basic transformation

[0025] ①Backfill of sand and gravel foundation layer

[0026] After the surface of the ash water absorption layer 3 is relatively flat, a sandstone foundation layer 4 with a thickness of h2 of 50 cm is backfilled on the upper part of the ash water absorption layer 3. The size of the slabs used in the sandstone foundation layer 4 is L=20-40 cm in one direction, and the thickness of the middle is not less than 15 cm. Sandstone is used to fill the gaps in the slabs. The mass of the filled sandstone particles with a particle size greater than 0.5 mm accounts for more than 50% of the total mass, the clay content is less than 2%, and the maximum particle size does not exceed 2 mm; the sandstone foundation layer 4 is mechanically rolled, and the foundation bearing capacity is tested after rolling. The next step of construction is carried out when it reaches more than 75% of the design value;

[0027] ②Backfill of crushed stone base layer

[0028] Backfill the gravel foundation layer on the upper part of the sandstone foundation layer 4. The gravel foundation layer is constructed in two layers according to the particle size: first, lay the lower geogrid 8-1 of model EGA100*100 on the sandstone foundation layer 4, then backfill the lower gravel foundation layer 5 with a thickness of h3 of 40cm, and the gravel particle size d2 of the lower gravel foundation layer 5 is 15mm~30mm. After backfilling, mechanical rolling is used for 5 times. After leveling, the upper geogrid 8-2 of model EGA100*100 is laid, and then the upper gravel foundation layer 6 with a thickness of h4 of 40cm is backfilled. The gravel particle size d3 of the upper gravel foundation layer 6 is 2mm~15mm. After backfilling, mechanical rolling is used for 5 times. After the foundation bearing capacity test reaches 100% or more of the design value after rolling and leveling, the next step of construction can be carried out;

[0029] S3: Backfill with silty clay cushion

[0030] A silty clay cushion layer 7 with a thickness of h5 of 30 cm is backfilled on the upper crushed stone foundation layer 6, and the top surface of the foundation is further leveled by mechanical rolling to ensure the foundation stability of the drainage open channel 9 built thereon and to ensure the construction quality of the drainage open channel 9.

[0031] After the utility model method was applied in the construction of a closed reservoir drainage open channel of a surrounding dammed red mud reservoir, compared with the traditional crushed stone compaction, the construction cost was reduced by 37.6%, the construction working days were reduced by 38.5%, and the safe operation of the closed reservoir drainage system and the stability of the red mud reservoir were ensured.

Claims

1. A foundation structure for a closed drainage channel of a red mud reservoir, wherein a red mud undercut line (1) is provided at the red mud (2) position of the planned drainage channel (9), and characterized in that: It is constructed by backfilling and laying an ash water absorption layer (3) on the lower excavation line of red mud (1), a sand and gravel foundation layer (4), a lower geogrid (8-1), a lower crushed stone foundation layer (5), an upper geogrid (8-2), an upper crushed stone foundation layer (6), and a silty clay cushion layer (7) in sequence from bottom to top.

2. The foundation structure of a closed drainage channel for a red mud reservoir as claimed in claim 1, characterized in that: The thickness h1 of the ash water absorption layer (3) is 40 to 65 cm; the thickness h2 of the sandstone foundation layer (4) is 40 to 65 cm; the thickness h3 of the lower crushed stone foundation layer (5) is 30 to 50 cm; the thickness h4 of the upper crushed stone foundation layer (6) is 30 to 50 cm; and the thickness h5 of the silty clay cushion layer (7) is 20 to 40 cm.

3. The foundation structure of a closed drainage open channel of a red mud reservoir as claimed in claim 1, characterized in that: The size L of the slabs used in the slab sandstone foundation layer (4) is 20-40 cm in one direction, and the thickness in the middle is not less than 15 cm. Sandstone is used to fill the gaps in the slab stone layer.

4. A foundation structure for a closed drainage channel of a red mud reservoir as claimed in claim 1, 2 or 3, characterized in that: The thickness of the ash water absorption layer (3) is h1 = 40 cm to 60 cm; the thickness of the sandstone foundation layer (4) is h2 40 to 60 cm.

5. The foundation structure of the red mud reservoir closed drainage open channel according to claim 4, characterized in that: The thickness h3 of the lower crushed stone foundation layer (5) is 35 cm to 45 cm, and the thickness h4 of the upper crushed stone foundation layer (6) is 35 cm to 45 cm.

6. The foundation structure of the red mud reservoir closed drainage open channel according to claim 5, characterized in that: The thickness h5 of the silty clay cushion layer (7) is 25 to 36 cm.

7. The foundation structure of the red mud reservoir closed drainage open channel according to claim 6, characterized in that: The models of the lower geogrid (8-1) and the upper geogrid (8-2) are EGA100*100.

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