Open pit coal mine slope structure and construction process thereof

Abstract

The invention relates to the technical field of open-pit coal mine mining, in particular to an open-pit coal mine slope structure and a construction technology thereof.The open-pit coal mine slope structure comprises a plurality of step platforms which are continuously arranged, retaining walls are arranged on the side faces of the step platforms, and the retaining walls are obliquely arranged in the first direction; the step platform is provided with transition planes extending in the horizontal direction, and the two ends, in the first direction, of the retaining wall are connected with the two adjacent transition planes correspondingly. Wherein an included angle a is formed between the first direction and the horizontal direction, and the included angle a is larger than or equal to 40 degrees and smaller than or equal to 60 degrees. According to the open pit coal mine side slope structure, the angle of the side slope can be effectively increased, so that the land occupancy rate is reduced, the coal mining rate is increased, meanwhile, the stability of the side slope can be guaranteed, and smooth coal mining is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of open-pit coal mining, and in particular to an open-pit coal mine slope structure and a construction process thereof. Background Art

[0002] The slope angle of an open-pit coal mine refers to the angle between the slope surface of the open-pit coal mine and the horizontal plane. It is a key parameter in the design and safe production of open-pit coal mines. The size of the slope angle directly affects the stability of the open-pit mine slope. For example, a steeper slope angle means that the slope is more inclined to the vertical direction and its stability is relatively poor; while a gentler slope angle can make the slope more stable, but it will occupy more land area for soil discharge, etc.

[0003] At present, the slope angle of open-pit coal mines is generally less than or equal to about 35°, which occupies a large area of ​​land for soil discharge, affecting the coal mining rate. If you want to increase the slope angle, it will affect the stability of the slope and affect the normal progress of coal mining. Summary of the invention

[0004] The present invention provides an open-pit coal mine slope structure and a construction process thereof. The open-pit coal mine slope structure can effectively increase the angle of the slope, thereby reducing the land occupation rate and improving the coal mining rate. At the same time, it can ensure the stability of the slope and ensure the smooth progress of coal mining.

[0005] In the first aspect, an embodiment of the present invention provides an open-pit coal mine slope structure, comprising a plurality of stepped platforms arranged continuously, retaining walls being arranged on the sides of the stepped platforms, the retaining walls being inclined along a first direction, the stepped platforms having a transition plane extending along a horizontal direction, and the two ends of the retaining wall along the first direction are respectively connected to two adjacent transition planes; wherein an angle a is formed between the first direction and the horizontal direction, and the angle a satisfies: 40°≤a≤60°.

[0006] In a possible implementation manner, the retaining wall has a first plane that is flush with the transition plane and a first inclined plane that is inclined along a first direction.

[0007] In a possible implementation, a grouting pipe is pre-buried in the step platform, and the grouting pipe is extended along a first direction and is used to cast a retaining wall on the side of the step platform, and the casting hole of the grouting pipe is located in the first plane.

[0008] In a possible implementation, two rows of grouting pipes are arranged, one row of grouting pipes is adjacent to the first inclined surface, and the other row of grouting pipes is away from the first inclined surface, and the two rows of grouting pipes are arranged in an alternating manner.

[0009] In a possible implementation, a drainage pipe is pre-buried in the stepped platform. A water inlet hole is opened on the drainage pipe. One end of the drainage pipe extends to the first slope of the retaining wall to drain water in the stepped platform to the first slope.

[0010] In a possible implementation, two rows of drain pipes are arranged, wherein the distance between one row of drain pipes and the transition plane is 1.5m-2.5m, and the distance between the other row of drain pipes and the transition plane is 5m-15m, and the two rows of drain pipes are arranged alternately.

[0011] In a possible implementation, a drainage ditch is provided on the transition plane adjacent to the retaining wall, and the drainage ditch is used to receive water discharged from the drainage pipe and drain the received water away.

[0012] In the second aspect, an embodiment of the present invention provides a construction process for the above-mentioned open-pit coal mine slope structure, comprising the following steps: pre-burying a grouting pipe: pre-burying a grouting pipe along a first direction on the slope; filling with earth and stone: filling the slope with earth and stone to fill the grouting pipe; pouring double-liquid slurry: pouring double-liquid slurry through a grouting pipe, and the double-liquid slurry is integrated with the earth and stone on the side of the slope to form a retaining wall; slope cleaning: cleaning the earth and stone on the outside of the retaining wall outside the slope to form a plurality of stepped platforms continuously arranged along the first direction on the slope.

[0013] In a possible implementation, a drainage pipe is pre-buried in the stepped platform, and the construction process also includes pre-buried drainage pipes before the step soil and stone landfill: the drainage pipes are pre-buried in the slope, and the drainage pipes and grouting pipes are staggered.

[0014] In a possible implementation, two rows of grouting pipes are arranged, one row of which is adjacent to the first slope, and the other row of which is away from the first slope, and the two rows of grouting pipes are arranged alternately; the double-liquid slurry pouring includes: the first pouring, pouring the grouting pipes adjacent to the first slope, until the double-liquid slurry seeps out from the bottom of the slope, and then stopping the grouting; the second pouring, after the double-liquid slurry of the first pouring solidifies, pouring the grouting pipes away from the first slope, the pressure at the grouting hole reaches more than 4MPa, and the minimum pump volume is kept at a stable pressure for more than 30 minutes, and then the grouting is ended.

[0015] The open-pit coal mine slope structure and its construction process provided by the present invention, the open-pit coal mine slope structure is configured to be a plurality of step platforms continuously arranged along a first direction, and a relatively strong retaining wall is formed on the side of each step platform, thereby improving the stability of each step platform, and can increase the inclination angle of each step platform, thereby realizing an increase in the inclination angle of the entire slope, and can increase the angle of the slope from the original 35° to 40°-60°, thereby reducing the land occupancy rate, improving the coal mining rate, and at the same time ensuring the stability of the slope, ensuring the smooth progress of coal mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The present invention is a schematic structural diagram of an open-pit coal mine slope structure.

[0018] Figure 2 It is a structural schematic diagram of an open-pit coal mine slope structure in the prior art.

[0019] Figure 3 The present invention provides a flow chart of an open-pit coal mine slope structure construction process.

[0020] Figure 4 The present invention provides another flow chart of an open-pit coal mine slope structure construction process.

[0021] Reference numerals: X, first direction; 1. Step platform; 11. Retaining wall; 111. First plane; 112. First slope; 12. Transition plane; 13. Drainage ditch; 2. Grouting pipe; 3. Drain pipe. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Combine the following Figure 1 An open-pit coal mine slope structure provided by an embodiment of the present invention is described, comprising a plurality of continuously arranged step platforms 1, a retaining wall 11 is arranged on the side of the step platform 1, the retaining wall 11 is arranged obliquely along a first direction X, the step platform 1 has a transition plane 12 extending in a horizontal direction, and the two ends of the retaining wall 11 along the first direction X are respectively connected to two adjacent transition planes 12; wherein an angle a is formed between the first direction X and the horizontal direction, and the angle a satisfies: 40°≤a≤60°. Specifically, the retaining wall 11 can be a concrete wall, a mortar-laid stone wall, a gabion retaining wall, etc.

[0024] In the present invention, by setting the slope into a plurality of stepped platforms 1 continuously arranged along the first direction X, and forming a relatively strong retaining wall 11 on the side of each stepped platform 1, the stability of each stepped platform 1 is improved, and the inclination angle of each stepped platform 1 can be increased, thereby achieving an increase in the inclination angle of the entire slope, and the angle of the slope can be increased from the original 35° to 40°-60°, thereby reducing the land occupancy rate and improving the coal mining rate. At the same time, the stability of the slope can be guaranteed, and the smooth progress of coal mining can be guaranteed.

[0025] Specifically, by setting the slope angle to 40°-60°, the limitation of 35° in the prior art is significantly broken through. Figure 2 As shown, due to stability considerations, traditional open-pit coal mine slopes generally adopt smaller slope angles, such as 35°, which results in the need to occupy a large amount of land for soil discharge. This solution uses the coordinated design of the step platform 1 and the retaining wall 11 to increase the slope's inclination while maintaining stability. Specifically, the horizontally extended transition plane 12 of the step platform 1 provides a safe space for equipment operation and personnel operations, and the inclined setting of the retaining wall 11 generates a downward component of force through its own weight, thereby enhancing the slope's anti-slip ability. This structural design reduces the slope's footprint by 30%-40%, while ensuring the slope's safety factor.

[0026] Among them, in open-pit coal mining, the slope angle is a key parameter. Properly increasing the slope angle can reduce the space occupied by coal resources reserved for maintaining slope stability. For example, the traditional slope angle may cause a large amount of coal to be buried under the slope protection range and cannot be mined. By adopting appropriate construction technology to increase the slope angle, more coal that was originally considered to be a protective slope and could not be mined can be mined, thereby directly increasing the recoverable reserves of coal and improving the mining rate of coal mines.

[0027] In addition, during open-pit coal mining, it is necessary to strip away the rock and soil covering the coal seam. Lowering the slope angle will increase the stripping range, while increasing the slope angle can reduce the stripping range. For example, if the slope angle is increased from 30° to 40°, the volume of rock and soil to be stripped will be significantly reduced at the same mining depth and horizontal mining range. This can reduce the workload of the stripping operation and reduce the stripping cost, including equipment investment, energy consumption and labor costs.

[0028] Furthermore, a reasonable increase in the slope angle helps optimize the mining space layout of the entire open-pit coal mine. When the slope angle is increased, the shape and spatial distribution of the stope will change, and the operation route and space of the mining equipment can be arranged more effectively. For example, it can provide a wider operating platform and a more reasonable moving route for large-scale mining equipment, avoid frequent adjustments of direction and position of the equipment during operation, and improve mining efficiency.

[0029] Moreover, since increasing the slope angle can increase the amount of coal mined and reduce the amount of stripping, the resource utilization rate of the entire coal mine is improved. For some open-pit coal mines with limited reserves, this means that mining can be continued for a longer period of time. Assuming that an open-pit coal mine is closed due to resource depletion after 10 years of mining according to the original plan, its service life may be extended to 12-15 years after the construction process of increasing the slope angle increases the recoverable reserves.

[0030] In some embodiments, the retaining wall 11 has a first plane 111 that is flush with the transition plane 12 and a first inclined surface 112 that is inclined along the first direction X.

[0031] In the present invention, the structure of the retaining wall 11 is specifically optimized, and a horizontal first plane 111 and an inclined first slope 112 are set. This double-sided structural design has significant advantages over the traditional single-slope retaining wall 11: the first plane 111 and the transition plane 12 are set in parallel to form a stable support surface, avoiding the problem of stress concentration at the connection between the traditional retaining wall 11 and the platform; the inclined design of the first slope 112 uses the gravity effect to provide additional anti-slip force, while facilitating drainage and preventing water accumulation. This structure is also convenient for later maintenance and overhaul, significantly improving the efficiency of engineering construction.

[0032] Specifically, the first plane 111 of the retaining wall 11 is connected to the transition plane 12, and can provide a safe space for equipment operation and personnel operation together with the transition plane 12. Moreover, the setting of the first plane 111 makes the retaining wall 11 have a certain thickness perpendicular to the first direction X. Specifically, the thickness of the retaining wall 11 perpendicular to the first direction X is 1.5m-2.5m. By increasing the thickness of the retaining wall 11, the reinforcement effect of the side of the step platform 1 is ensured, the stability of the single step platform 1 structure is ensured, and then the stability of the entire slope structure is ensured.

[0033] In some embodiments, a grouting pipe 2 is pre-buried in the stepped platform 1 , and the grouting pipe 2 is extended along the first direction X, and is used to cast a retaining wall 11 on the side of the stepped platform 1 , and the casting hole of the grouting pipe 2 is located in the first plane 111 .

[0034] In the present invention, the traditional retaining wall 11 is often constructed by cast-in-place or prefabricated installation, which is difficult to construct and difficult to control the quality. In this solution, the grouting pipe 2 is extended along the first direction X, and the pouring hole is located in the first plane 111. This design ensures the uniform distribution of concrete during the pouring process. Through the grouting pipe 2 system, the pouring pressure and pouring amount can be accurately controlled, so that the retaining wall 11 is fully combined with the slope soil to form a more integrated support structure.

[0035] Specifically, the pouring hole is located in the first plane 111, and the grouting pipe 2 is extended along the first direction X. After the pouring is completed through the grouting pipe 2, a retaining wall 11 inclined along the first direction X can be formed on the slope, and no prefabrication and installation are required, which reduces the construction difficulty and construction cost. After the pouring is completed and the retaining wall 11 is formed, since the pouring hole is located in the first plane 111, the first plane 111 of the retaining wall 11 can be formed, and by cleaning the soil and rocks outside the first plane 111, a transition plane 12 flush with the first plane 111 can be obtained.

[0036] Among them, the grouting pipe 2 uses a PDC plastic pipe with a diameter of about 80-100mm, and the length is usually 20-30m (determined according to the height of the slope of medium and large open-pit mines). Holes are opened on the PDC plastic pipe body, and the hole diameter is generally designed to be about 15-20mm. The holes are arranged in a plum blossom pile style to make a grouting flower pipe.

[0037] In some embodiments, the grouting pipes 2 are arranged in two rows, one row of the grouting pipes 2 is adjacent to the first inclined surface 112 , and the other row of the grouting pipes 2 is away from the first inclined surface 112 , and the two rows of the grouting pipes 2 are arranged alternately.

[0038] In the present invention, the pouring effect is further optimized by arranging two rows of staggered grouting pipes 2. The two rows of grouting pipes 2 adjacent to the first inclined surface 112 and away from the first inclined surface 112 are staggered to ensure full coverage of the pouring range. This arrangement avoids the dead angle problem that may occur in traditional single-row pouring. At the same time, the staggered arrangement of the two rows of pipes reduces the pressure at a single pouring point, thereby improving the pouring uniformity and pouring quality.

[0039] Specifically, during pouring, a row of grouting tubes 2 adjacent to the first slope 112 is poured first. After the pouring and solidification, a relatively stable first slope 112 can be formed. Then, a row of grouting tubes 2 away from the first slope 112 is poured. Since the first slope 112 has been formed before, the pouring at this time can increase the pressure at the grouting holes to ensure the diffusion distance of the grouting and form a retaining wall 11 that is as thick as possible. On the other hand, by increasing the pressure at the grouting holes, the density of the slurry is increased, and the structural strength of the retaining wall 11 is further improved.

[0040] Optionally, three or four rows of grouting pipes 2 can be used, and pouring can be performed row by row from close to the first slope 112 to away from the first slope 112, which can further improve the thickness and structural strength of the retaining wall 11. However, the increase in the number of rows of grouting pipes 2 also means an increase in cost.

[0041] Preferably, the present invention adopts two rows of grouting pipes 2 so that the thickness of the retaining wall 11 reaches about 2m, thereby ensuring the structural strength of the side of the stepped platform 1 so that the inclination angle of the slope can meet the structural strength requirements when it is 40° to 60°.

[0042] In some embodiments, a drainage pipe 3 is pre-buried in the stepped platform 1 , a water inlet hole is opened on the drainage pipe 3 , and one end of the drainage pipe 3 extends to the first slope 112 of the retaining wall 11 for draining water in the stepped platform 1 to the first slope 112 .

[0043] In the present invention, a complete drainage system is constructed by pre-burying the drainage pipe 3 in the stepped platform 1. Traditional slopes often have the risk of poor drainage and water accumulation causing landslides. In this solution, the water inlet holes on the drainage pipe 3 can collect the water accumulated on the platform in time, and drain the water out through the pipe extending to the first inclined surface 112, effectively preventing the accumulation of water inside the slope. This design not only improves the stability of the slope, but also reduces soil erosion.

[0044] Specifically, water is easily accumulated in the slope of an open-pit coal mine on rainy days. By setting up a drainage pipe 3, the moisture in the stepped platform 1 can enter the drainage pipe 3 through the water inlet hole, and then be discharged to the first slope 112 through the drainage pipe 3. The first slope 112 of the retaining wall 11 is erosion-resistant, and water can flow away through the first slope 112 to prevent moisture from accumulating in the slope.

[0045] Specifically, the open-pit mine has platforms on each layer to facilitate coal transportation and traffic, and slope care requires the design of a drainage system. The drainage pipe 3 uses a PDC plastic steel pipe with a diameter of about 200m, and a hole is opened on the steel pipe body. The hole diameter is generally designed to be about 20-25mm, and the holes are arranged in a plum blossom pile style to form a water inlet. The drainage pipe 3 can be tilted toward the direction of the drainage outlet, so that the water entering the drainage pipe 3 through the water inlet hole can be smoothly discharged from the first inclined surface 112.

[0046] In some embodiments, the drain pipes 3 are arranged in two rows, wherein the distance between one row of the drain pipes 3 and the transition plane 12 is 1.5m-2.5m, and the distance between the other row of the drain pipes 3 and the transition plane 12 is 5m-15m, and the two rows of drain pipes 3 are arranged alternately.

[0047] In the present invention, a layered and partitioned drainage network is formed by arranging two rows of staggered drainage pipes 3 and clearly specifying the distances (1.5m-2.5m and 5m-15m) from the transition plane 12. This precise spacing design ensures the coverage and drainage efficiency of the drainage system and avoids the problems of drainage dead corners or uneven drainage capacity that may be caused by traditional random arrangement.

[0048] Specifically, the buried depth of drainage pipe 3 is designed, and the buried depth is also before discharging soil and rocks. The exposed section of the slope is about 0.2-0.5m as a solid pipe. The buried depth of drainage pipe 3 is designed to be 2 rows. The first row is designed to be 2m below the transition platform, and the second row is designed to be 5-15m below the platform. It is specifically determined according to the height of the slope. The two rows are staggered in a plum blossom pile style. The horizontal buried drainage pipe 3 should be staggered with the grouting pipe 2, or the drainage pipe 3 should be set slightly inclined.

[0049] In some embodiments, a drainage ditch 13 is provided on the transition plane 12 adjacent to the retaining wall 11 , and the drainage ditch 13 is used to receive the water discharged from the drainage pipe 3 and drain the received water away.

[0050] In the present invention, the entire drainage system is improved by arranging the drainage ditch 13 on the transition plane 12. The arrangement of the drainage ditch 13 provides an effective collection channel for the water discharged from the drainage pipe 3, and can discharge the water from the slope area in time. This design forms a complete drainage chain of "collection-drainage-discharge", which significantly improves the waterproof and drainage capacity of the slope.

[0051] Specifically, the drainage ditch 13 is arranged on the transition plane 12 and is arranged close to the first inclined surface 112, so that the water flowing down the first inclined surface 112 can directly enter the drainage ditch 13 and then be discharged through the drainage ditch 13. Specifically, the drainage ditch 13 can be set at a certain inclination angle along the extension direction, so that the water entering the drainage ditch 13 can be discharged in time and smoothly. Specifically, the drainage ditch 13 can be set in the form of one side high and one side low along the extension direction, or it can be set in the form of high in the middle and low at both ends. In order to improve the anti-scouring performance of the drainage ditch 13, a waterproof layer, such as asphalt, can be laid in the drainage ditch 13 to prevent water from seeping into the slope again in the drainage ditch 13, and to improve the anti-scouring performance of the drainage ditch 13.

[0052] The open-pit coal mine slope structure improves the stability of each step platform 1 by setting the slope into a plurality of step platforms 1 continuously arranged along a first direction X, and forming a relatively strong retaining wall 11 on the side of each step platform 1, so that the inclination angle of each step platform 1 can be increased, thereby achieving an increase in the inclination angle of the entire slope, and the angle of the slope can be increased from the original 35° to 40°-60°, thereby reducing the land occupancy rate, improving the coal mining rate, and at the same time ensuring the stability of the slope and ensuring the smooth progress of coal mining.

[0053] like Figure 3-4 As shown, an embodiment of the present invention provides a construction process for the above-mentioned open-pit coal mine slope structure, comprising the following steps: S1, pre-buried grouting pipe 2: pre-buried grouting pipe 2 along the first direction X on the slope; S2, soil and stone removal: soil and stone removal from the slope to fill the grouting pipe 2; S3, double liquid slurry pouring: pouring double liquid slurry through the grouting pipe 2, the double liquid slurry and the side soil and stone of the slope are integrated into one, forming a retaining wall 11; S4, side slope cleaning: cleaning the soil and rocks outside the retaining wall 11 outside the side slope, and forming a plurality of step platforms 1 continuously arranged along the first direction X on the side slope.

[0054] In the present invention, the construction process of the slope structure of the open-pit coal mine includes four key steps: pre-buried grouting pipe 2, landfill of soil and rocks, double-liquid slurry pouring and slope cleaning. Compared with the traditional construction method, this process has significant advantages: by pre-buried grouting pipe 2, the cumbersome process of traditional on-site excavation and pouring channel is avoided, and the construction efficiency is improved; the landfill process of soil and rocks is precisely matched with the position of grouting pipe 2, ensuring that the slurry can fully penetrate and combine with the soil during subsequent pouring; the double-liquid slurry pouring process enables the slurry to fully integrate with the soil and rocks on the slope to form a retaining structure with strong integrity, which has better structural stability than the traditional single pouring or prefabricated installation method; the setting of the slope cleaning step ensures that the final step platform 1 has a regular structure, which is convenient for later use and maintenance.

[0055] Specifically, the earth and stone are removed by a self-dumping transport vehicle, and the stripped earth and stone are transported to the slope for removal, and the grouting pipe 2 and the drainage pipe 3 fixed in advance are buried and piled up to form a slope.

[0056] Among them, the grouting material is generally selected as a fast-setting material. This design uses a double-liquid slurry material, a mixture of cement and water glass. Polyester materials can also be used, but the cost is higher than that of double-liquid slurry.

[0057] Double liquid slurry is used for plugging or reinforcement in general construction projects. This time it is mainly for slope reinforcement. The water-cement ratio (mass ratio) of cement slurry is generally controlled at around 0.8-1.0, that is, the mass of water is 0.8-1.0 times the mass of cement. For example, 1 kg of cement is matched with 0.8-1 kg of water. The volume ratio of water glass to cement slurry is usually between 0.5-1.0. Assuming that the volume of cement slurry is 1 liter, the volume of water glass is 0.5-liter. Cement mainly plays a cementing role. Water glass (aqueous solution of sodium silicate) can react with calcium hydroxide, a cement hydration product, to form a gelling calcium silicate gel. This gel can fill gaps, improve the density of the material, and enhance the plugging and reinforcement effects.

[0058] Double liquid slurry is used to make acid-resistant concrete: the mass ratio of cement (usually acid-resistant cement): water glass: sodium fluorosilicate (curing agent) is about 1: (0.6-0.7): 0.15. For example, 100 kg of acid-resistant cement is matched with 60-70 kg of water glass and 15 kg of sodium fluorosilicate. Acid-resistant cement itself has certain acid resistance. Water glass reacts with sodium fluorosilicate to form a complex silica gel network structure inside the concrete, which improves the acid resistance and strength of the concrete and enables it to resist the erosion of acidic media.

[0059] In some special soil reinforcement projects, cement paste (water-cement ratio 0.5-0.7) is mixed with water glass solution (modulus 2.6-3.3, Baume degree 38-43) at a volume ratio of 1:0.3-0.5. Cement and water glass react between soil particles, making the soil particles cemented together, improving the bearing capacity and stability of the soil, and reducing the permeability of the soil. In practical applications, it is necessary to determine the most appropriate cement-water glass ratio through experiments based on specific engineering conditions (such as temperature, humidity, construction technology, etc.) and requirements for material properties (such as strength, setting time, etc.).

[0060] In some embodiments, a drainage pipe 3 is pre-buried in the stepped platform 1, and the construction process also includes S5, which is located before the step of draining soil and rock filling, and pre-buried drainage pipe 3: pre-buried drainage pipe 3 in the slope, and drainage pipe 3 and grouting pipe 2 are staggered.

[0061] In the present invention, the pre-embedding timing of the drainage pipe 3 is arranged before the landfill of soil and rocks, avoiding structural damage caused by later excavation and installation; the design of staggered arrangement of the drainage pipe 3 and the grouting pipe 2 prevents mutual interference between the two pipeline systems; this pre-embedding method ensures the integration of the drainage system and the slope structure, and improves the drainage efficiency; the reasonable arrangement of the pre-embedding process reduces construction interference and improves construction efficiency and quality. Compared with the common method of later excavation and installation of drainage facilities in the prior art, this design significantly improves the reliability and durability of the drainage system.

[0062] In some embodiments, two rows of grouting pipes 2 are arranged, one row of grouting pipes 2 is adjacent to the first inclined surface 112, and the other row of grouting pipes 2 is away from the first inclined surface 112, and the two rows of grouting pipes 2 are arranged alternately; double-liquid slurry casting includes: S31, first pouring, pouring the grouting pipe 2 adjacent to the first slope 112, until the double liquid slurry seeps out from the bottom of the slope, and then stopping the grouting; S32, the second pouring, after the double liquid slurry of the first pouring solidifies, pouring is performed on the grouting pipe 2 away from the first slope 112, the pressure at the grouting hole reaches above 4MPa, and the minimum pump volume is maintained at a constant pressure for more than 30min, and the grouting is finished.

[0063] In the present invention, the first pouring is for the grouting pipe 2 adjacent to the first slope 112 until the double-liquid slurry seeps out from the bottom, which ensures sufficient reinforcement of the bottom of the slope; the second pouring is carried out after the double-liquid slurry of the first pouring solidifies, which avoids mutual interference of the slurries and ensures the effect of each pouring; the second pouring sets clear pressure indicators (above 4MPa) and time requirements (pressure stabilization for more than 30min), and this precise process parameter control ensures the pouring quality; the staggered arrangement of the two rows of grouting pipes 2 and the method of pouring in batches ensure that the slurry can fully penetrate into all parts of the slope.

[0064] This multi-step pouring process has significant advantages over traditional single pouring: it improves the uniformity of slurry penetration; avoids slurry cross-flow; ensures the integrity of the slope structure; and improves the controllability of construction quality.

[0065] In a specific embodiment, the open-pit coal mine slope structure construction process provided by the present invention includes: S1. Pre-buried grouting pipe 2: The grouting pipe 2 is designed and fixed in advance at an angle of 40-60°, and buried deep when discharging soil and rocks. The grouting holes are generally designed to be arranged in 2 rows, with the hole spacing designed at 3m and the row spacing designed at 2m. The two rows of holes are also arranged in a staggered plum blossom pile style.

[0066] S5. Drainage pipe 3 pre-buried: Design the buried depth of drainage pipe 3, also before the soil and stone are discharged, the exposed section of the slope is about 0.2-0.5m as a solid pipe, and design the buried depth of drainage pipe 3 in 2 rows. The first row is designed to be 2m below the transition platform, and the second row is designed to be 5-15m below the platform. The specific depth is determined according to the height of the slope. The two rows are staggered in a plum blossom pile arrangement. The horizontal burial of drainage pipe 3 should be staggered 40-60° with the grouting pipe 2.

[0067] S2. Earth and stone removal: After the grouting pipe 2 and the drainage pipe 3 are fixed, the stripped earth and stone are transported to the slope by a self-dumping transport vehicle for earth and stone removal, and the grouting pipe 2 and the drainage pipe 3 fixed in advance are buried and piled up to form a slope.

[0068] S3, double liquid slurry pouring: first fill the first row of grouting holes (close to the slope), inject the prepared double liquid slurry into the grouting holes through the grouting pump and grouting pipe, observe the slope, and stop grouting if the slurry seeps out to the bottom of the slope. The double liquid slurry solidifies quickly. After waiting for 24 hours, grout the second row of grouting holes. In order to ensure the grouting diffusion distance, the grouting hole pressure reaches more than 4MPa, and the minimum pump volume is stable for more than 30 minutes, then the grouting is finished.

[0069] S4. Slope cleaning: Use an excavator to clean up the remaining soil and rocks outside the slope, and leave a drainage ditch 13 outside the bottom of the slope.

[0070] The open-pit coal mine slope structure and construction process provided by the present invention have the following beneficial effects: 1. Economic benefits (1) Reduce mining costs Reducing the amount of stripping is one of the significant economic advantages brought by the construction process of improving the slope angle. In open-pit coal mining, the cost of stripping operations accounts for a high proportion. For example, the stripping cost of each cubic meter of rock and soil, including excavation, transportation and disposal, may reach about 10-20 yuan. By increasing the slope angle and reducing the stripping range, the volume of stripped rock and soil is greatly reduced, thereby reducing the stripping cost. At the same time, due to the optimization of the mining space layout, the operating efficiency of the mining equipment is improved. Large mining equipment such as electric shovels and trucks can operate more efficiently, reducing the idling time and ineffective operation trips of the equipment. Taking the electric shovel as an example, the operating efficiency may be increased by 10%-20%. Correspondingly, the equipment energy consumption and operating costs per unit of coal mining are reduced, increasing the economic benefits of the coal mine.

[0071] (2) Increase coal resource recovery Increasing the slope angle can make it possible to mine coal resources that were originally unminable due to slope stability requirements. For some areas where the coal seams are shallow but close to the slope, this part of the coal can be effectively mined after the slope angle is appropriately increased. This increases the recoverable reserves of coal and improves the recovery rate of coal resources. For example, in an open-pit coal mine with a reserve of 100 million tons, the construction process of increasing the slope angle may increase the recoverable coal by 10-20 million tons, bringing huge economic benefits to coal mining companies.

[0072] 2. Safety and benefits (1) Slope stability assurance A construction process to improve the slope angle is usually combined with advanced slope monitoring and reinforcement technology. For example, during the construction process, high-precision slope displacement monitoring equipment will be installed to monitor the slight deformation of the slope in real time. Once abnormal displacement is found, reinforcement measures can be taken in time, such as prestressed anchor reinforcement, anti-slide pile setting, etc. These measures can ensure the stability of the slope during the mining process while improving the slope angle, and reduce the occurrence of safety accidents such as slope landslides.

[0073] The construction process also takes into account the mechanical properties of the rock and soil and the hydrogeological conditions of the slope. Through detailed engineering geological surveys of the rock and soil, the reasonable increase in the slope angle is determined. For example, for areas with high rock and soil strength and less groundwater impact, the slope angle can be appropriately increased; while for areas with loose rock and soil and abundant groundwater, a cautious increase strategy will be adopted, and waterproofing and reinforcement measures will be strengthened to ensure the long-term stability and safety of the slope.

[0074] (2) Improvement of working environment safety Reducing the amount of stripping means reducing the amount of rock excavation and transportation work in open-pit coal mining. This reduces dust pollution caused by rock and soil transportation and improves the air quality at the work site. At the same time, it reduces the frequent activities of excavation and transportation equipment in the mining site, reduces the risk of accidents such as equipment collisions, and creates a safer working environment for miners.

[0075] 3. Environmental benefits (1) Reduce land occupation and destruction Due to the reduction in stripping volume, the area of ​​the spoil dump for discarding rock and soil is reduced accordingly. The construction of an open-pit coal mine spoil dump will occupy a large amount of land, and the spoil dumping process may cause pressure and damage to the surrounding land. By increasing the slope angle and reducing the stripping volume, the land demand of the spoil dump can be reduced and the damage to land resources can be reduced. For example, the area of ​​a large open-pit coal mine spoil dump may be reduced from several hectares to tens of hectares, which is of great significance for protecting land resources and the ecological environment.

[0076] (2) Reducing ecosystem disturbance Reducing the stripping range and the area of ​​the dumping site can reduce the damage to the surrounding vegetation. Vegetation plays an important role in maintaining water and soil, regulating climate and maintaining ecological balance. Reducing the damage to vegetation caused by mining activities is conducive to protecting the local ecosystem. At the same time, reducing dust emissions during the excavation and transportation of rock and soil also reduces pollution and interference to the living environment of surrounding animals and plants, promoting the stability of the ecosystem and the protection of biodiversity.

[0077] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An open-pit coal mine slope structure, characterized in that: The invention comprises a plurality of stepped platforms (1) arranged in series, a retaining wall (11) being arranged on the side of the stepped platform (1), the retaining wall (11) being arranged obliquely along a first direction, the stepped platform (1) having a transition plane (12) extending in a horizontal direction, and two adjacent transition planes (12) being respectively connected at both ends of the retaining wall (11) along the first direction; The first direction forms an angle a with the horizontal direction, and the angle a satisfies: 40°≤a≤60°.

2. The open-pit coal mine slope structure according to claim 1, characterized in that: The retaining wall (11) has a first plane (111) that is flush with the transition plane (12) and a first inclined surface (112) that is inclined along the first direction.

3. The open-pit coal mine slope structure according to claim 2, characterized in that: A grouting pipe (2) is pre-buried in the stepped platform (1); the grouting pipe (2) is extended along the first direction and is used to cast the retaining wall (11) on the side of the stepped platform (1); the casting hole of the grouting pipe (2) is located in the first plane (111).

4. The open-pit coal mine slope structure according to claim 3, characterized in that: The grouting pipes (2) are arranged in two rows, one row of the grouting pipes (2) is adjacent to the first inclined surface (112), and the other row of the grouting pipes (2) is away from the first inclined surface (112), and the two rows of the grouting pipes (2) are arranged in a staggered manner.

5. The open-pit coal mine slope structure according to any one of claims 2 to 4, characterized in that: A drainage pipe (3) is pre-buried in the stepped platform (1), a water inlet hole is provided in the drainage pipe (3), one end of the drainage pipe (3) extends to the first inclined surface (112) of the retaining wall (11), and is used to drain water in the stepped platform (1) to the first inclined surface (112).

6. The open-pit coal mine slope structure according to claim 5, characterized in that: The drainage pipes (3) are arranged in two rows, wherein the distance between the drainage pipes (3) in one row and the transition plane (12) is 1.5 m-2.5 m, and the distance between the drainage pipes (3) in the other row and the transition plane (12) is 5 m-15 m, and the two rows of drainage pipes (3) are arranged in a staggered manner.

7. The open-pit coal mine slope structure according to claim 5, characterized in that: A drainage ditch (13) is provided on the transition plane (12) adjacent to the retaining wall (11), and the drainage ditch (13) is used to receive water discharged from the drainage pipe (3) and drain the received water.

8. A construction process for an open-pit coal mine slope structure according to any one of claims 3 to 7, characterized in that: The steps include: Pre-buried grouting pipe (2): pre-buried grouting pipe (2) along a first direction on the slope; Discharging earth and rocks to fill: discharging earth and rocks from the slope to fill the grouting pipe (2); Double-liquid slurry pouring: pouring double-liquid slurry through the grouting pipe (2), the double-liquid slurry is integrated with the side soil and rocks of the slope to form a retaining wall (11); Slope cleaning: cleaning the soil and rocks outside the retaining wall (11) outside the slope, and forming a plurality of stepped platforms (1) continuously arranged along the first direction on the slope.

9. The construction process of the open-pit coal mine slope structure according to claim 8, characterized in that: A drainage pipe (3) is pre-buried in the stepped platform (1), and the construction process further comprises pre-buried drainage pipes (3) before the soil and rock filling step: pre-buried drainage pipes (3) in the slope, and the drainage pipes (3) and the grouting pipes (2) are staggered.

10. The construction process of the open-pit coal mine slope structure according to claim 8, characterized in that: The grouting pipes (2) are arranged in two rows, one row of the grouting pipes (2) is adjacent to the first inclined surface (112), and the other row of the grouting pipes (2) is away from the first inclined surface (112), and the two rows of the grouting pipes (2) are arranged alternately; the double-liquid slurry casting comprises: The first pouring is to pour the grouting pipe (2) adjacent to the first slope (112) until the double-liquid slurry seeps out from the bottom of the slope, and then stop the grouting; During the second pouring, after the double-liquid slurry of the first pouring solidifies, pouring is performed on the grouting pipe (2) away from the first inclined surface (112), and the pressure at the grouting hole reaches above 4 MPa and the minimum pump volume is maintained at a constant pressure for more than 30 minutes, and the grouting is completed.

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