Drainage system based on waste gully treatment filled with coal gangue and construction method

Abstract

The invention relates to the technical field of slope protection engineering, in particular to a drainage system based on waste gully treatment filled with coal gangue and a construction method. The system comprises three parts: 1, a slope closure drainage structure; 2, an upstream flood discharge and drainage pipeline; and 3, a leachate collecting pipeline and a construction method thereof. According to the design, a method of combining zoned water drainage, water guide and water drainage is put forward, scouring of rainfall to the slope surface of the washout ditch can be reduced to the maximum extent from the construction period to the operation period, meanwhile, combination with other supporting structures is facilitated, and safety of the slope surface of the washout ditch is guaranteed. 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] This invention patent relates to the field of slope protection engineering technology, and in particular to a drainage system and construction method based on the treatment of barren gullies filled with coal gangue. Background Technology

[0002] Coal gangue is a large-scale solid waste generated during coal resource development, including stripping, tunneling, mining, washing, and processing, accounting for approximately 10% to 20% of coal mining output. Currently, the comprehensive utilization of coal gangue in my country has evolved from "primarily storage" to a combination of storage and utilization, finding applications in fuel, building materials, roadbed fillers, chemical raw materials, agricultural production, and filling. However, these comprehensive utilization technologies still cannot meet China's current requirements for centralized, high-yield, and large-scale coal gangue processing. Furthermore, the historical accumulation of gangue from long-term coal mining is enormous, forming gangue mountains in mining areas. These mountains not only occupy vast amounts of land but also pollute the atmosphere, water bodies, and soil, becoming a persistent problem for regional development in the Loess Plateau coal mining areas.

[0003] Coal gangue filling in barren gullies is a technical method for ecological restoration and management of barren gullies in mining areas. It aims to achieve a win-win situation of comprehensive utilization of coal gangue and ecological management of barren gullies, improving the stability and biodiversity of the ecosystem. In the Shanxi, Shaanxi, and Inner Mongolia regions, coal gangue is mainly used to fill coal mining subsidence areas or barren gullies to create land, which can be seen as a continuation of the coal gangue filling and reclamation technology. However, the dam body is affected by rainfall and upstream floods, leading to increased water content in the soil and rock, resulting in reduced strength and making the dam body prone to instability. Simultaneously, continuous heavy rainfall erodes the slope surface, causing significant loss of soil and rock, further reducing stability and seriously affecting the safety of the dam body and subsequent management work. Therefore, drainage system protection is a crucial aspect of slope engineering.

[0004] In the subsequent protection work of ecological restoration of barren gullies based on coal gangue filling technology, intercepting ditches need to be installed on the top of the dam slope to prevent backflow of rainwater, and drainage pipes need to prevent upstream water from impacting the dam body. The construction quality of the intercepting ditches and drainage pipes directly affects the smooth progress of subsequent construction and ecological restoration procedures. Currently, brick-built intercepting ditches are used, which are prone to soil settlement and deformation during the rainy season. These brick-built ditches are also prone to leakage due to settlement cracks at the bottom and sides of the ditches caused by soil settlement. In addition, the rigid water flow surface of the intercepting ditches is formed by concrete pouring, which is easily affected by thermal expansion and contraction, leading to cracking of the surface concrete and water seepage. Both of these situations can cause water to seep into the slope soil through cracks, rendering the slope protection ineffective and leading to slope collapse. Summary of the Invention

[0005] The purpose of this application is to provide a slope interception and drainage structure, upstream flood discharge and drainage pipeline, leachate collection pipeline, and construction method suitable for ecological management technology of coal gangue-filled barren gullies. It adopts a combination of zoned drainage, water diversion, and drainage methods, which can minimize the erosion of the barren gully slope by rainfall from the construction period to the operation period. At the same time, it is easy to combine with other support structures to ensure the safety of the barren gully slope, thereby solving at least one of the technical problems involved in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution of this application is as follows:

[0007] The site's surface runoff drainage system consists of transverse drainage (rectangular), transverse drainage ditches at the front edge of the site top, and longitudinal intercepting ditches (rectangular) on both banks.

[0008] Horizontal drainage ditch: The horizontal drainage ditch is designed with a rectangular cross section, 0.8 meters wide and 1.0 meter high. The foundation is made of 2:8 cement-soil (by mass) compacted to a thickness of 0.2 meters, and is then masonry with 10-meter mortar-grouted rubble masonry to a thickness of 0.3 meters.

[0009] Transverse drainage ditch at the front edge of the site top: Located 6.0 meters from the front edge of the site top at elevation 1188, the transverse drainage ditch is designed with a trapezoidal cross section, with a bottom width of 1.0 meter, a height of 1.0 meter, and a slope ratio of 1:1. The foundation is treated with 2:8 cement-soil (by mass) compaction, with a thickness of 0.2 meters.

[0010] Longitudinal intercepting ditch: To reduce flooding within the site and ensure site safety, a perimeter intercepting structure is constructed along the edge of the waste rock pile to control floodwaters outside the ditch edge from entering the waste rock pile area and divert them to the bottom of the ditch outside the site. The longitudinal intercepting ditch is designed with a rectangular cross-section, 2 meters wide and 1.5 meters high. The foundation is constructed using a 2:8 cement-soil mixture (by mass) compacted to a thickness of 0.2 meters, and then masonry with rubble masonry to a thickness of 0.3 meters.

[0011] Floodwater upstream of the site is discharged downstream through drainage culverts.

[0012] However, during the waste rock removal process, a very small amount of rainwater will seep into the bottom of the ditch from the top. Therefore, it is necessary to bury seepage collection pipes and delivery pipes at the bottom of the ditch to discharge the seepage water in the ditch to the downstream seepage collection pool for use in site and road watering, so as to prevent it from polluting natural water bodies.

[0013] To ensure timely drainage of water seepage from the ditch, the leachate is discharged downstream via φ50 flexible permeable pipes to two leachate collection ponds for treatment. (See attached images for details.) Figure 6 The leachate collection tank is square, with an inner diameter of 400 cm in length and 400 cm in width, and a depth of 200 cm. The foundation consists of 20 cm thick excavated and compacted soil, and the top layer is 20 cm thick concrete.

[0014] The advantages and positive effects of this invention are: Installing drainage systems at the bottom and slopes of the landfill helps remove leachate from the waste and reduces the risk of leakage. Timely removal of leachate can reduce the impact of waste on groundwater. The landfill slopes also require seepage prevention measures to prevent rainwater from seeping into the landfill. Applying an impermeable coating to the slope surface, installing drainage pipes, and constructing flood discharge facilities are all effective measures to control rainwater leakage and maintain the stability of the landfill. Attached Figure Description

[0015] Figure 1 Design drawing for a horizontal drainage ditch;

[0016] Figure 2 Design drawing of the transverse drainage ditch at the leading edge of the top of the storage yard;

[0017] Figure 3 This is a detailed drawing of the longitudinal intercepting ditch;

[0018] Figure 4 This is a structural diagram of a flood drainage culvert.

[0019] Figure 5 Cross-sectional view of the leachate collection pipeline;

[0020] Figure 6 This is a leachate collection tank.

Claims

1. A drainage system and construction method based on coal gangue filling of barren gullies, including steps such as slope interception drainage structure, upstream flood discharge drainage pipeline, leachate collection pipeline and its construction method.

Images