Open mining pit anti-seepage structure

Abstract

The utility model relates to an anti-seepage structure of an open mining pit, which solves the problem that catchment water cannot be prevented from entering the mining pit through surface water seepage around the boundary by a common water interception and drainage method. Comprising a boundary outer retaining wall located on the edge of a mining pit, an annular waterproof counter-slope section and a water intercepting and draining ditch, the annular waterproof counter-slope section is tightly attached to the boundary outer retaining wall of the mining pit and inclines towards the outside of the pit, and the inclination angle is 1%-3%; the annular waterproof reverse slope section is composed of a clay impermeable layer and a rain wash resistant layer located on the clay impermeable layer. And the clay impermeable layer is formed by compacting rock soil with low permeability and high compaction rate from inside or outside the mining pit. And the rain wash resistant layer is formed by compacting rock soil with strong wash resistance from the inside or the outside of the mining pit. The width of the annular waterproof reverse slope section is not smaller than H1, and H1 is the thickness of a mining pit earth surface weathered layer. The structure is simple in construction and reliable in process, and weakening and collapse risks caused by water seepage of the ground surface outside the boundary of the mining pit upper side slope are greatly reduced.

Description

Technical Field

[0001] The utility model belongs to the field of open pit drainage, and in particular relates to an open pit anti-seepage structure. Background Art

[0002] Drainage and flooding is a key task in open-pit mines, especially deep pit mines. Especially in areas with heavy rainfall, the quality of drainage and flooding work directly affects the progress of mining and production and slope safety. Drainage and flooding in open-pit mines mainly include three categories: drainage outside the boundary, mechanical drainage of relay pump stations in the pit, and drainage of drainage wells. At present, the commonly used drainage and flooding structures outside the boundary of deep pit open pits are mainly in the form of retaining walls and drainage ditches, that is, a retaining wall with a certain height and width is constructed outside the boundary of the mining pit, or a flood control ditch is excavated outside the boundary according to the terrain, or a combination of the two.

[0003] The above-mentioned commonly used interception and drainage structures have a common disadvantage, that is, they can only prevent water from flowing outside the boundary from directly flowing into the pit from the surface, but cannot prevent the water from entering the mining pit through surface seepage around the boundary, and seeping to the mining pit slope along the cracks of the weak bedding, seeping out from the slope surface into the pit, and while scouring the surface of the slope below the seepage point, it also brings out the loose rock and soil particles inside the upper slope, causing the mechanical balance of the rock and soil inside the slope to be broken, increasing the risk of slope collapse.

[0004] The Chinese invention "A Comprehensive Management Method for Spoil Dumps (CN103061327B)" also involves reverse slopes and anti-seepage layers, but (1) its application field and protection object are spoil dumps; (2) its anti-seepage layer is made of clay material. Although it has a certain degree of anti-seepage function, its anti-scouring ability is relatively weak. In areas with frequent heavy rains, after a few heavy rains, the anti-seepage layer will be washed away and lose its anti-seepage function. Utility Model Content

[0005] The utility model provides an open pit anti-seepage structure, thereby solving the problem that the commonly used interception and drainage methods cannot prevent the collected water from entering the pit through surface seepage around the boundary.

[0006] The utility model is realized by the following technical solutions:

[0007] An open pit anti-seepage structure comprises an outer retaining wall located at the edge of the pit, an annular waterproof reverse slope section and an intercepting and draining ditch. The annular waterproof reverse slope section is close to the outer retaining wall of the pit and is inclined outward of the pit with an inclination angle of 1% to 3%. The intercepting and draining ditch is outside the annular waterproof reverse slope section. The annular waterproof reverse slope section is composed of a clay anti-seepage layer and a rainwater scouring resistance layer located on the clay anti-seepage layer.

[0008] The clay anti-seepage layer is formed by compacting some rock and soil with low permeability and high compaction rate selected from inside or outside the mining pit.

[0009] The compaction degree of clay anti-seepage layer is ≥93% and the saturated permeability coefficient is ≤1×10 -7 cm / s, and the thickness after compaction is 0.25 to 0.35 meters.

[0010] The rainwater erosion-resistant layer is formed by compacting some rock and soil with strong erosion resistance selected from inside or outside the mining pit.

[0011] The compaction degree of the rain erosion resistance layer is ≥93%, and the thickness after compaction is 0.15 to 0.25 meters.

[0012] The width of the annular waterproof reverse slope section shall not be less than H1 meter, where H1 meter is the thickness of the surface weathering layer of the mining pit.

[0013] The utility model provides an open pit anti-seepage structure, which forms an annular waterproof reverse slope section by discharging qualified rock and soil outside the boundary of the open pit, so as to prevent surface water from seeping into the pit and weakening the slope. The construction is simple and the process is reliable, which can greatly reduce the weakening and landslide risk of the upper slope of the pit caused by surface water seepage outside the boundary, thereby reducing the economic expenditure of slope cutting and load reduction required for landslide control, and also reducing the operational safety risk of personnel and vehicles in the pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a plan view of the utility model;

[0015] Figure 2 It is a structural sectional view of the utility model. DETAILED DESCRIPTION

[0016] The utility model aims to provide an open pit anti-seepage method, that is, to form a reverse slope by discharging qualified rock and soil outside the boundary of the open pit, and to consider the construction of supporting retaining walls and drainage ditches in combination with the terrain. It prevents the collected water from entering the pit through surface seepage around the boundary, and seeping to the pit slope along the cracks of the weak bedding, seeping from the slope surface into the pit, and scouring the surface of the slope below the seepage point, while also bringing out the loose rock and soil particles inside the upper slope, causing the mechanical balance of the rock and soil inside the slope to be broken, increasing the risk of slope collapse.

[0017] Before the pit begins to be stripped or after a period of stripping, select some rock and soil with low permeability, high compaction rate and strong resistance to rainwater erosion from the surrounding area or in the pit, discharge them to the outside of the pit layer by layer, and compact them appropriately to form a circular waterproof reverse slope section with a certain width, reasonable structure and inclined toward the outside of the pit. Combined with the actual terrain, drainage ditches and retaining walls can be constructed outside the circular waterproof reverse slope section.

[0018] The specific implementation plan is as follows:

[0019] like Figure 1 , 2As shown, before the pit starts to be stripped or after a period of stripping, the trees and other debris around the pit boundary are cleared, and the surface soil with a thickness of H2+H3 is stripped in advance along the inclination direction outside the pit at a horizontal slope of 1% to 3%;

[0020] Select some rock and soil with low permeability and high compaction rate (such as clay) from inside or outside the pit, transport it by car and place it around the surface of the pit. Use a bulldozer to push it into a circular waterproof reverse slope section with a width of about H1 meter and tilted toward the outside of the pit (lateral slope of 1% to 3%), and then use a roller to compact it appropriately, with a compaction degree ≥93% and a saturated permeability coefficient ≤1×10 -7 cm / s, and the thickness after compaction is H3 meters.

[0021] Select some rock and soil with strong erosion resistance (such as gravel) from inside or outside the pit, transport it by car and place it on the above-mentioned clay anti-seepage layer, use a bulldozer to push it into a circular waterproof reverse slope section with a width of H1 meter and inclined toward the outside of the pit (slope 1% to 3%), then use a roller to compact it appropriately, with a compaction degree ≥93%, and the thickness after compaction is H2 meters.

[0022] In consideration of the actual terrain, an intercepting drainage ditch is constructed outside the circular waterproof reverse slope section to divert the collected water away from the mining pit.

[0023] The annular waterproof reverse slope section is close to the outer retaining wall of the mining pit boundary, which prevents surface water from seeping into the pit and can be used as a ring pit road for daily driving patrol inspections.

[0024] The width of the annular waterproof reverse slope section is set to be no less than H1 meter. This is because the thickness of the surface weathering layer is H1 meter. The rock and soil permeability above this depth is the highest and the rock properties are the worst, making it most susceptible to water seepage and slope collapse. When the width of the annular waterproof reverse slope section is less than H1 meter, there is still a high probability that surface seepage water outside the waterproof reverse slope will flow into the pit from the upper slope of the mining pit located in the weathering layer through soil cracks, causing the slope to weaken and increase the risk of collapse.

[0025] The thickness of the annular waterproof reverse slope section is H2+H3 cm in total. If it is too thin, it cannot form an effective anti-seepage layer, and if it is too thick, it will cause greater pressure on the slope and increase the risk of slope collapse.

[0026] Example:

[0027] Take an open pit as an example. The overall rock quality is poor. The upper weathering layer contains a lot of talc and other rock properties. The surface weathering layer is 50 meters thick. The rainfall in the rainy season is large and rainstorms occur frequently. In order to prevent the foreign water from flowing into the pit through the surface infiltration, causing internal scouring and weakening of the weathering layer slope, causing landslide danger:

[0028] Before the pit is stripped, trees and other debris around the pit boundary should be cleared;

[0029] Select some clay with low permeability and high compaction rate from outside the pit, transport it by car and place it around the surface of the pit. Use a bulldozer to push it into a circular waterproof reverse slope section 2 with a width of 50 meters, a thickness of about 0.30 meters, and a slope toward the outside of the pit (lateral slope of 2%). Then use a roller to compact it appropriately, with a compaction degree ≥93% and a saturated permeability coefficient ≤1×10 -7 cm / s;

[0030] Select some gravels with strong anti-scouring ability from outside the pit, transport them by car and place them on the clay anti-seepage layer 6, use a bulldozer to push them into a circle of 50 meters wide, 0.20 meters thick, and inclined toward the outside of the pit (lateral slope 2%). The anti-rainwater scouring layer 7 is then appropriately compacted with a roller, and the compaction degree is ≥93%;

[0031] In consideration of the actual terrain, an intercepting drainage ditch 1 is constructed outside the annular waterproof reverse slope section to divert the collected water away from the mining pit.

[0032] The annular waterproof reverse slope section is close to the retaining wall 3 outside the boundary, which prevents surface water from seeping into the pit and can be used as a pit-circling road for daily driving patrol inspection.

[0033] The width of the annular waterproof reverse slope section is set to 50 meters, considering that the thickness of the surface weathering layer is 50 meters. The rock and soil 8 above this depth has the highest permeability and the worst rock properties, and is most susceptible to water seepage, causing the slope 5 to slide.

[0034] The annular waterproof reverse slope section has a total thickness of 0.5 meters. If it is too thin, it cannot form an effective anti-seepage layer, and if it is too thick, it will cause greater pressure on the slope 5 and increase the risk of slope collapse.

[0035] In the utility model:

[0036] The width is set to be no less than H1 meter, considering that the thickness of the surface weathering layer is H1 meter. The rock and soil permeability above this depth is the highest and the rock properties are the worst, which is most susceptible to water seepage and slope collapse. When the width of the circular waterproof reverse slope section is less than H1 meter, the surface seepage outside the waterproof reverse slope is still likely to flow into the pit from the upper slope of the mining pit located in the weathering layer through soil cracks, causing the slope to weaken and increase the risk of landslide; the thickness is H2+H3 centimeters in total. If it is too thin, it will not form an effective anti-seepage layer, and if it is too thick, it will cause greater pressure on the slope and increase the risk of slope collapse;

[0037] It contains two layers of structure, 6 with low permeability and high compaction rate and 7 with strong anti-scouring ability, with the inclination direction facing away from the mining pit 4 and the lateral slope of 1% to 3%;

[0038] The clay anti-seepage layer 6 is made by selecting some rock and soil (such as clay) with low permeability and high compaction rate from inside or outside the pit, transporting it by car and discharging it around the surface of the pit, and using a bulldozer to push it into a circular waterproof reverse slope section with a width of about H1 meter and tilted toward the outside of the pit (lateral slope of 1% to 3%), and then using a roller to appropriately compact it, with a compaction degree ≥93% and a saturated permeability coefficient ≤1×10 -7 cm / s, the thickness after compaction is H3 meters;

[0039] The rainwater scour resistant layer 7 is selected from some rock and soil (such as gravel) with strong scour resistance from inside or outside the pit, transported by car and discharged onto the above-mentioned clay anti-seepage layer, and pushed by a bulldozer into a circular waterproof reverse slope section with a width of H1 meter and inclined toward the outside of the pit (slope 1% to 3%), and then appropriately compacted by a roller, with a compaction degree ≥ 93%, and a thickness of H2 meters after compaction;

[0040] The outer retaining wall 3 is close to the boundary of the mining pit to prevent surface water from seeping into the pit. At the same time, it can be used as a ring road around the pit for daily driving patrol inspection.

[0041] According to the actual terrain, a retaining wall 3 and an intercepting drainage ditch 1 can be constructed to prevent surface water from flowing into the mining pit 4.

Claims

1. An open pit anti-seepage structure, Its characteristics are: It includes an outer retaining wall located at the edge of the mining pit, an annular waterproof reverse slope section and an intercepting and draining ditch. The annular waterproof reverse slope section is close to the outer retaining wall of the mining pit and tilted toward the outside of the pit. The intercepting and draining ditch is outside the annular waterproof reverse slope section. The annular waterproof reverse slope section is composed of a clay anti-seepage layer and a rainwater scour resistance layer located on the clay anti-seepage layer.

2. An open pit anti-seepage structure according to claim 1, Its characteristics are: The angle of the annular waterproof reverse slope section inclining toward the outside of the pit is 1% to 3%.

3. The open pit anti-seepage structure according to claim 1, Its characteristics are: The clay anti-seepage layer is formed by compacting some rock and soil with low permeability and high compaction rate selected from inside or outside the mining pit.

4. An open pit anti-seepage structure according to claim 3, Its characteristics are: The compaction degree of clay anti-seepage layer is ≥93% and the saturated permeability coefficient is ≤1×10 -7 cm / s, and the thickness after compaction is 0.25 to 0.35 meters.

5. The open pit anti-seepage structure according to claim 1, Its characteristics are: The rainwater erosion-resistant layer is formed by compacting some rock and soil with strong erosion resistance selected from inside or outside the mining pit.

6. An open pit anti-seepage structure according to claim 5, Its characteristics are: The compaction degree of the rain erosion resistance layer is ≥93%, and the thickness after compaction is 0.15 to 0.25 meters.

7. The open pit anti-seepage structure according to claim 1, Its characteristics are: The width of the annular waterproof reverse slope section is not less than H 1 , where H 1 is the thickness of the weathering layer on the surface of the mining pit.

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