CN113123351A - Method for treating hidden danger of tailings dam in plateau alpine region - Google Patents

Abstract

The invention discloses a hidden danger treatment method for a tailing dam in a plateau alpine region, which comprises the following steps of (1) manually forming a part of dry beach by transporting tailing in a reservoir region to the front of an initial dam by an automobile; (2) adopting a geomembrane to perform anti-seepage treatment on the hillside; (3) treating the seepage points of the east dam body of the initial dam in a diversion mode; (4) reverse filtering bodies are additionally arranged at the contact positions of the two sides of the middle mountain and the dam body; (5) and (4) treating the landslide appearing in the middle mountain by adopting a slope cutting and ballasting mode. The invention effectively solves a series of problems of the tailings dam in the early stage of the tailings pond in the east-west dam and the middle mountain of the east-west dam by adopting the original method for treating the hidden danger of the tailings dam in the alpine region of the plateau, and eliminates the hidden danger. After the treatment is finished, the east-west dam bodies and the middle mountain bodies at the initial stage of the tailing pond keep a good stable state in the normal ore discharge work of the tailing pond of the subsequent concentrating mill, and the expected treatment effect is achieved.

Description

Method for treating hidden danger of tailings dam in plateau alpine region

Technical Field

The invention relates to a method for treating hidden danger of a tailing dam in a plateau alpine region.

Background

A certain tailing pond is located at the plateau with the altitude of 2850 meters and is a valley type tailing pond, and a primary dam is arranged at a ditch opening. The initial dam body consists of an east dam body and a west dam body, an original mountain body is used as one part of the dam body between the east dam body and the west dam body, the mountain body between the east dam body and the west dam body has a serious collapse phenomenon after the tailing pond is put into operation for 10 days, a large-range landslide is formed, cracks appear on the surface of the mountain body, and the width of the cracks is 50-300 mm. Partial longitudinal cracks appear on the top surface of the east initial dam, the width of the cracks is 5 mm-70 mm, and the maximum depth of the cracks is 1500 mm. Meanwhile, the dam abutment part of the dam body close to the middle mountain body has the settlement displacement phenomenon. After hidden danger occurs, tailing discharging operation in the dam area is stopped immediately, observation points are set, and a specially-assigned person measures the tailing discharging operation at regular time, and the observation results show that after tailing discharging to the reservoir area is stopped, displacement of each observation point of the dam body gradually tends to be stable after a period of time. Aiming at the problems of the tailing dam, experts in the aspects of organizing rock and soil, designing and constructing tailing ponds carry out analysis and demonstration, the properties, the causes and the influence degree of the tailings are analyzed, and a treatment scheme is formulated.

Disclosure of Invention

The invention aims to provide a method for treating hidden dangers of a tailing dam in a plateau alpine region, which can effectively solve the problem of the initial dam of a tailing pond, eliminate the hidden dangers and ensure that the tailing dam keeps a good stable state in the normal ore discharge engineering of the tailing pond.

The invention aims to realize the method for treating the hidden danger of the tailings dam in the alpine region of the plateau,

(1) manually forming a part of dry beach by transporting the tailings in the reservoir area to the front of the initial dam by an automobile;

(2) adopting a geomembrane to perform anti-seepage treatment on the hillside, wherein the geomembrane adopts a finished product of two cloth films and one film, the geotextiles at two sides of the film adopt a pure polyester material with strong durability, the breaking strength is more than or equal to 14kN/m, the total mass of the geotextiles in unit area is more than 800 g/m 2, the middle film material adopts an environment-friendly HDPC film, the thickness of the film material is more than or equal to l and 5mm, the permeability coefficient is less than or equal to l and 0-7cm/s, the lap joint in the geomembrane laying process adopts hot melt welding, the lap joint width of a welding line is about 100 +/-20 mm, the fusion welding temperature is set to be 420 +/-20 ℃, the fusion welding speed is set to be 2 m/;

(3) treating the seepage points of the east dam body of the initial dam in a diversion mode; leading the east dam seepage guiding blind ditch to a downstream slope toe from a water outlet point, excavating a blind ditch with the depth of 600mm and the width of not less than 2.5m on a dam surface from the water outlet point to the dam toe, fully paving geotextile with the width of 6m at the bottom, arranging a steel flower filter pipe with the diameter of 200mm in the blind ditch, externally covering the filter pipe with geotextile, filling pebbles in the blind ditch until the depth of 200mm is below the dam surface, fully paving geotextile on the pebble surface, covering a pebble protective layer with the thickness of not less than 200mm on the geotextile until the dam surface is flat after observing for 5 days, if the filter pipe is settled, additionally paving pebbles until the dam surface is flat, finally recovering the rock blocks on the dam surface to the original state, sealing a pipe head at a water outlet position by using a rhombic steel mesh, externally covering the geotextile, newly arranging a filter body with the depth of 1.2m, the thickness of 1m and the width of 3m at the dam toe after the construction of the seepage guiding blind ditch, and leading;

(4) the contact part of the two sides of the middle mountain and the dam body is additionally provided with a reverse filter: excavating 4-5m of earthwork outside the drainage ditch, wherein the height of the surface of the earthwork is equal to that of the drainage ditch, the steps are chamfered to form a slope surface with the ratio of 1:2 or less, and 1 inverted filter is arranged between the drainage ditch and the slope surface, and the concrete method comprises the following steps: the anti-filtering body is horizontally arranged along the drainage ditch in a mountain direction according to the width of 2m, the thickness of the anti-filtering body vertical to the slope surface is 1.0m, the outer edge and the drainage ditch keep a safe distance when a base groove of the anti-filtering body is excavated, the drainage ditch is prevented from being damaged by side inclination, geotechnical cloth with the thickness not less than 500 g/square meter is laid at the contact part of the anti-filtering body and the mountain surface, and sand gravel or pebble with the thickness of 800mm is covered on the surface layer of the geotechnical; pressing and covering the surface layer of sand gravel or pebbles with the thickness of not less than 200mm with pebbles or block stones;

(5) treating landslide occurring in the middle mountain by adopting a slope cutting and ballasting mode, namely, carrying out lower part stacking and back pressure; the elevation of the top of the slope pressing body is 2798m, the top width is 15m, and the downstream slope is 1: 2; the porosity of the waste stone after rolling of the slope body is not more than 30 percent; the upper part is unloaded, cut and replaced; arranging a platform with the width of about 10.0m at 2820.0m elevation outside a downstream drainage ditch at the top of the initial dam, then cutting a slope in the downstream direction according to the average gradient of 1:3, excavating and filling stone materials in a sliding area with a slope formed below 2810m elevation, wherein the stone materials can be taken from waste piles of a sand and stone yard; thirdly, surface water is treated; in order to guide out the seepage orderly, drainage ditches are arranged on the inner sides of the platforms, and the drainage ditches are built at the positions of the bank slopes on the two sides to guide water to the downstream.

Analyzing the reasons of cracks generated at the top of the initial dam and landslide of the middle mountain:

(1) the dam foundation corner gravel layer locally contains perennial island-shaped frozen soil which is thawed when meeting water and then is thawed; or the dam body directly contacts the water surface, so that the earth and stone materials of the dam are disintegrated when meeting water, the shear strength index of the earth and stone materials is reduced, the compressibility is increased, and plastic deformation is generated, and local non-uniform settlement of the dam body is caused due to local deformation.

(2) In the process of mineral separation test production, the concentration of discharged tailings is low, so that the length of a deposited dry beach formed in front of a dam is insufficient, and the water surface in the dam directly contacts the dam surface of the initial dam, so that fine-particle sandy soil in the dam body is lost.

(3) Because landslide occurs in the middle mountain part area of the east-west initial dam, the landslide body drives the dam abutment of the east-west dam to displace to generate cracks.

(4) The original terrain slope of the mountain body in the middle of the east and west initial dams is about 1:3-1:4 (about 14-18 degrees), the terrain is gentle, the soil material of the mountain body is high in silt content, and the soil quality is loose. In the process of constructing the aqueduct groove of the tailing pond, the slope toe of the mountain forms an empty surface due to excavation, so that the south slope surface has local collapse. When the tailings pond is used for drawing ores, because the length of the primary dry beach is short, water in the pond area enters a mountain to form dam-surrounding seepage, the seepage quantity of underground water of the mountain is increased, and the shear strength index of a soil body is reduced.

(5) Along with the discharge of tailings, the water level in the tailing pond is raised, and seepage water enters a landslide area from a gap of a middle mountain body, so that the soil body of the structural surface is saturated in water, the strength is reduced, and the fluidity is increased.

The invention effectively solves a series of problems of the tailings dam in the early stage of the tailings pond in the east-west dam and the middle mountain of the east-west dam by adopting the original method for treating the hidden danger of the tailings dam in the alpine region of the plateau, and eliminates the hidden danger. After the treatment is finished, the east-west dam bodies and the middle mountain bodies at the initial stage of the tailing pond keep a good stable state in the normal ore discharge work of the tailing pond of the subsequent concentrating mill, and the expected treatment effect is achieved.

Drawings

The present invention will be described in further detail below with reference to the accompanying drawings.

FIG. 1 is a schematic view of the diversion construction of the present invention;

FIG. 2 is a schematic view of the construction of slope cutting and ballast in the present invention;

in the figure: 1 is an initial dam body; 2 is a dry masonry layer; 3, a dam seepage guiding blind ditch; 4 is a flow guide pipe; 5 is a backwater ditch; 6 is a drainage ditch; 7 is a slope cutting area; 8 is a replacement area; 9 is a slope pressing platform; 10 is a slope pressing area; 11 is geotextile; 12 is a hypothetical sliding surface; and 13 is a drainage ditch.

Detailed Description

A method for treating hidden danger of tailings dams in alpine regions in plateaus, as shown in figures 1 and 2,

(1) the tailings in the reservoir area are transported to the front of the initial dam by an automobile to artificially form a part of dry beach, so that the impact of water on the dam body of the initial dam 1 in the tailing discharge process is effectively relieved;

(2) adopting a geomembrane 11 to perform anti-seepage treatment on a hillside, wherein the geomembrane adopts a finished product of two cloth films and one film, the geomembrane on two sides of the film adopts a pure polyester material with strong durability, the breaking strength is more than or equal to 14kN/m, the total mass of the unit area of the geomembrane is more than 800 g/m 2, the middle film material adopts an environment-friendly HDPC film, the thickness of the film material is more than or equal to l and 5mm, the permeability coefficient is less than or equal to l x l0-7cm/s, the lap joint in the geomembrane laying process adopts hot melt welding, the lap joint width of a welding seam is about 100 +/-20 mm, the hot melt welding temperature is set to be 420 +/-20 ℃, the hot melt welding speed is set to be 2m/min, the geomembrane is protected by a;

(3) treating the seepage points of the east dam body of the initial dam in a diversion mode; leading the east dam seepage guiding blind ditch 3 from a water outlet point to a downstream slope toe, excavating a blind ditch with the depth of 600mm and the width of not less than 2.5m on a dam face from the water outlet point to the dam toe, fully paving geotextile with the width of 6m at the bottom, arranging a steel flower filter pipe with the diameter of 200mm in the blind ditch, externally covering the filter pipe with geotextile, filling pebbles in the blind ditch until the depth of 200mm is below the dam face, fully paving geotextile on the pebble surface, covering a pebble protective layer with the thickness of not less than 200mm on the geotextile until the dam face is flat after observing for 5 days, if the cobbles are settled, then paving the pebbles until the dam face is flat, finally recovering the rock blocks on the dam face to the original shape, sealing a pipe head at the water outlet position by using a rhombic steel mesh, externally covering the geotextile, newly arranging a filter body with the depth of 1.2m, the thickness of 3m width at the dam toe after the construction of the seepage guiding blind ditch 3 is finished, and leading out the seepage;

(4) the contact part of the two sides of the middle mountain and the dam body is additionally provided with a reverse filter: excavating 4-5m of earthwork outside the drainage ditch, wherein the height of the surface of the earthwork is equal to that of the drainage ditch, the steps are chamfered to form a slope surface with the ratio of 1:2 or less, and 1 inverted filter is arranged between the drainage ditch and the slope surface, and the concrete method comprises the following steps: the anti-filtering body is horizontally arranged along the drainage ditch in a mountain direction according to the width of 2m, the thickness of the anti-filtering body vertical to the slope surface is 1.0m, the outer edge and the drainage ditch keep a safe distance when a base groove of the anti-filtering body is excavated, the drainage ditch is prevented from being damaged by side inclination, geotechnical cloth with the thickness not less than 500 g/square meter is laid at the contact part of the anti-filtering body and the mountain surface, and sand gravel or pebble with the thickness of 800mm is covered on the surface layer of the geotechnical; pressing and covering the surface layer of sand gravel or pebbles with the thickness of not less than 200mm with pebbles or block stones;

(5) treating landslide occurring in the middle mountain by adopting a slope cutting and ballasting mode, namely, carrying out lower part stacking and back pressure; the elevation of the top of the slope pressing body is 2798m, the top width is 15m, and the downstream slope is 1: 2; the porosity of the waste stone after rolling of the slope body is not more than 30 percent; the upper part is unloaded, cut and replaced; arranging a platform with the width of about 10.0m at 2820.0m elevation outside a downstream drainage ditch at the top of the initial dam, then cutting a slope in the downstream direction according to the average gradient of 1:3, excavating and filling stone materials in a sliding area with a slope formed below 2810m elevation, wherein the stone materials can be taken from waste piles of a sand and stone yard; thirdly, surface water is treated; in order to guide out the seepage orderly, drainage ditches are arranged on the inner sides of the platforms, and the drainage ditches are built at the positions of the bank slopes on the two sides to guide water to the downstream.

Claims (1)

1. A method for treating hidden danger of tailings dams in alpine plateau areas is characterized by comprising the following steps:

(1) manually forming a part of dry beach by transporting the tailings in the reservoir area to the front of the initial dam by an automobile;

(2) adopting a geomembrane to perform anti-seepage treatment on the hillside, wherein the geomembrane adopts a finished product of two cloth films and one film, the geotextiles at two sides of the film adopt a pure polyester material with strong durability, the breaking strength is more than or equal to 14kN/m, the total mass of the geotextiles in unit area is more than 800 g/m 2, the middle film material adopts an environment-friendly HDPC film, the thickness of the film material is more than or equal to l and 5mm, the permeability coefficient is less than or equal to l and 0-7cm/s, the lap joint in the geomembrane laying process adopts hot melt welding, the lap joint width of a welding line is about 100 +/-20 mm, the fusion welding temperature is set to be 420 +/-20 ℃, the fusion welding speed is set to be 2 m/;

(3) treating the seepage points of the east dam body of the initial dam in a diversion mode; leading the east dam seepage guiding blind ditch to a downstream slope toe from a water outlet point, excavating a blind ditch with the depth of 600mm and the width of not less than 2.5m on a dam surface from the water outlet point to the dam toe, fully paving geotextile with the width of 6m at the bottom, arranging a steel flower filter pipe with the diameter of 200mm in the blind ditch, externally covering the filter pipe with geotextile, filling pebbles in the blind ditch until the depth of 200mm is below the dam surface, fully paving geotextile on the pebble surface, covering a pebble protective layer with the thickness of not less than 200mm on the geotextile until the dam surface is flat after observing for 5 days, if the filter pipe is settled, additionally paving pebbles until the dam surface is flat, finally recovering the rock blocks on the dam surface to the original state, sealing a pipe head at a water outlet position by using a rhombic steel mesh, externally covering the geotextile, newly arranging a filter body with the depth of 1.2m, the thickness of 1m and the width of 3m at the dam toe after the construction of the seepage guiding blind ditch, and leading;

(4) the contact part of the two sides of the middle mountain and the dam body is additionally provided with a reverse filter: excavating 4-5m of earthwork outside the drainage ditch, wherein the height of the surface of the earthwork is equal to that of the drainage ditch, the steps are chamfered to form a slope surface with the ratio of 1:2 or less, and 1 inverted filter is arranged between the drainage ditch and the slope surface, and the concrete method comprises the following steps: the anti-filtering body is horizontally arranged along the drainage ditch in a mountain direction according to the width of 2m, the thickness of the anti-filtering body vertical to the slope surface is 1.0m, the outer edge and the drainage ditch keep a safe distance when a base groove of the anti-filtering body is excavated, the drainage ditch is prevented from being damaged by side inclination, geotechnical cloth with the thickness not less than 500 g/square meter is laid at the contact part of the anti-filtering body and the mountain surface, and sand gravel or pebble with the thickness of 800mm is covered on the surface layer of the geotechnical; pressing and covering the surface layer of sand gravel or pebbles with the thickness of not less than 200mm with pebbles or block stones;

(5) treating landslide occurring in the middle mountain by adopting a slope cutting and ballasting mode, namely, carrying out lower part stacking and back pressure; the elevation of the top of the slope pressing body is 2798m, the top width is 15m, and the downstream slope is 1: 2; the porosity of the waste stone after rolling of the slope body is not more than 30 percent; the upper part is unloaded, cut and replaced; arranging a platform with the width of about 10.0m at 2820.0m elevation outside a downstream drainage ditch at the top of the initial dam, then cutting a slope in the downstream direction according to the average gradient of 1:3, excavating and filling stone materials in a sliding area with a slope formed below 2810m elevation, wherein the stone materials can be taken from waste piles of a sand and stone yard; thirdly, surface water is treated; in order to guide out the seepage orderly, drainage ditches are arranged on the inner sides of the platforms, and the drainage ditches are built at the positions of the bank slopes on the two sides to guide water to the downstream.

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