Dam body design and construction method based on waste gully treatment filled with coal gangue

Abstract

The invention relates to the technical field of blocking dams, in particular to a dam body design and construction method based on waste gully management through coal gangue filling. The system comprises three parts: 1, initial dam body design; 2, designing a fill dam; and 3, stability analysis. A dam body design and construction method is designed and put forward, a stability analysis method for the stability of the original valley and the stability after backfilling is given, and the measures can effectively maintain the stability of a treatment site. The problems of land resource occupation and environmental destruction caused by coal mining can be practically solved, the land space can be expanded, the land utilization value is improved, the ecological environment of a mining area is improved, and land space greening treatment and agricultural cultivation soil fertility improvement are achieved.

Description

Technical Field

[0001] The patent of this invention relates to the technical field of retaining dams, in particular to a dam body design and construction method based on coal gangue filling and waste ditch management. Background Art

[0002] Gangue is a large amount of solid waste generated during the process of stripping, excavation, mining, washing, and processing of coal resources. Its output is about 10% to 20% of the coal mining volume. At present, the comprehensive utilization of gangue in my country has developed from "storage-oriented" to "combination of storage and use", and has been used in many fields such as fuel, building materials, roadbed fillers, chemical raw materials, agricultural production and filling. However, the above comprehensive utilization technology cannot meet China's current requirements for centralized, high-yield, and large-scale treatment of gangue; and the historical gangue accumulated in long-term coal mining and production is huge, and it is piled up in the mining area to form gangue mountains, which not only occupies a large amount of land, but also pollutes the atmosphere, water bodies, and soil to form pollution sources, becoming a "chronic disease" in the development of the coal mining area of ​​the Loess Plateau.

[0003] The technology of ecological management of waste ditch filled with coal gangue is a technical method for ecological restoration and management of waste ditch in mining area, aiming to achieve a win-win situation of comprehensive utilization of coal gangue and ecological management of waste ditch, and improve the stability and biodiversity of ecosystem. In Shanxi, Shaanxi and Inner Mongolia, coal gangue is mainly used to fill coal mining subsidence area or waste ditch to realize land reclamation, which can be regarded as the continuation of the technology of coal gangue filling and reclamation. However, the accumulation dam body is affected by rainfall and upstream floods, and the water content of rock and soil increases, resulting in reduced strength, which can easily cause the dam body to become unstable. At the same time, continuous heavy rainfall continues to scour the slope surface, causing a large amount of rock and soil on the slope surface to be lost, further reducing stability, and seriously affecting the safety of the dam body and subsequent management work. Therefore, the dam body design and its stability analysis are important contents of the retaining dam project.

[0004] The basis for constructing a technical system for ecological management of coal mine subsidence areas and gullies in the Loess Plateau using coal gangue as filling material is dam body design. Therefore, it is urgent to study the design and stability analysis of dam bodies built in coal mine subsidence areas and gullies using coal gangue as filling material, and form a complete set of design and construction methods. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a dam body design, stability analysis, and primary dam and accumulation dam construction method based on coal gangue filling and waste ditch management, thereby solving at least one technical problem involved in the background technology.

[0006] In order to solve the above technical problems, the technical solution of this application is as follows:

[0007] According to the local actual situation, the initial dam can be earth dam or rockfill dam, but compared with earth dam, rockfill dam requires a large amount of stone materials that meet the requirements, and the investment is relatively large. Earth dam has a greater degree of compaction and better stability, so it is more reasonable to choose earth dam between the two. Therefore, earth dam is preferred in the initial dam design.

[0008] Initial dam body design: Initial slag dam is built at the ditch mouth. The slag dam is filled with compacted earth and stone, with a slope ratio of 1:3.0, a dam height of 10m and a dam top width of 6m.

[0009] Comprehensive foundation clearing: Before the construction of the slag dam, the foundation should be cleared within the backfill reservoir area and within the 60-80cm widening of the dam slope angle line, and the grass, tree roots, and cultivated soil within the reservoir area, dam foundation, and dam shoulder should be removed. At the same time, loose sand and gravel blocks on the surface of the rock foundation, soil accumulation in the concave area, and protruding rocks should be removed. After the foundation is excavated, the contour is required to be smooth to avoid sudden changes in terrain. If a broken zone is found after excavation, it should be handled according to the specific situation. The thickness of the foundation clearing depends on the needs, and the excavation depth is 0.5m.

[0010] Dam shoulder slope cutting: The dam body and the bank slope should be connected smoothly with a slope. The slope of the soil bank slope below the dam crest elevation on both sides of the dam site should not be steeper than 1:1.0, and the slope of the soil bank slope above the dam crest elevation on both sides should not be steeper than 1:0.75 to prevent high slopes from sliding. If there is a landslide body, the landslide body should be completely removed. Therefore, the actual dam site has soil slopes below the dam crest elevation on both sides cut to 1:1, and the slope of the soil bank slope above the dam crest elevation on both sides cut to 1:0.75.

[0011] Culvert drainage: In order to prevent the seepage in the gangue pile from forming pipe bursts at the overflow point on the downstream slope and destroying the initial stability of the dam, a φ50 soft permeable pipe is installed at the bottom of the dam to drain to the seepage collection pool.

[0012] Design of the accumulation dam: After the initial earth dam is filled, it is stacked in steps according to the slope of 1:3.0. Each of the first three steps is 10.0m high (4.5m thick gangue, 0.5m thick soil), and the last two steps are 8m high (3.5m thick gangue, 0.5m thick soil). A 6m wide platform is reserved on each step as a horseway, which not only increases the stability of the gangue, but also facilitates the passage of vehicles and the collection and drainage of rainwater on the slope.

[0013] Stability analysis of the original valley: The loess valley stratum is mainly Lishi loess (Q2) stratum, with a visible thickness of 75m. The stability coefficients of the left and right dam bank slopes at 72m from the original valley mouth were calculated using the Morgenstern-Price method of the SLOPE / W module in GeoStudio software. The intersection of the valley ground line and the top surface of the horse trail at 72m from the valley mouth was determined as the shear entrance in the software, and the intersection of the valley ground line and the bottom surface of the horse trail was determined as the shear entrance. The sliding surface search was performed to obtain the stability coefficient of the valley slope.

[0014] Stability analysis after backfilling: When backfilling, start from the mouth of the ditch, pile up from the mouth of the ditch to the head of the ditch, and from bottom to top along the contour line, compact and pile up, and pile to the designed elevation. After the ditch is backfilled with coal gangue, its slope stability coefficient is calculated by automatically searching for the sliding surface by specifying the shear inlet and shear outlet. The design only considers the stability of the accumulation dam under natural conditions and rainstorm conditions. In the software, the intersection of the ditch ground line and the initial dam outer edge is determined as the shear outlet, and the intersection of the ditch ground line and the top surface of the accumulation dam is determined as the shear inlet. The sliding surface search is performed to obtain the stability coefficient of the ditch slope.

[0015] The present invention provides a dam design and construction method based on gangue filling for waste ditch management. The stability of high earth dam in the ditch is fully considered, a dam design and construction method is proposed, and a stability analysis method of the original ditch stability and the stability after backfilling is given. These measures can effectively maintain the stability of the management field. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the design drawing of the primary dam profile;

[0017] Figure 2 Design drawings for the reef dam;

[0018] Figure 3 This is the minimum stability coefficient analysis diagram of the left dam bank at 72 meters from the original valley mouth;

[0019] Figure 4 This is the minimum stability coefficient analysis diagram of the right dam bank at 72 meters from the original valley mouth;

[0020] Figure 5 Automatically search for the minimum stability coefficient analysis diagram of the sliding surface.

Claims

1. A dam body design and construction method based on gangue filling waste ditch management, including the steps of primary dam structure design, accumulation dam structure design, original ditch and backfill stability analysis and construction method.

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