阅读说明：本技术 一种山谷型生活垃圾填埋场安全开采方法及开采结构 (safe mining method and mining structure for valley type domestic garbage landfill ) 是由 吴军 李俊 韩诚 罗培康 朱俊伟 张铁军 陈欣琪 陈东标 杨智力 李志远 李丹阳 于 2019-08-29 设计创作，主要内容包括：本发明公开了一种山谷型生活垃圾填埋场安全开采方法及开采结构,属于固废资源化利用领域。开采方法包括开拓运输、排水、边坡稳定和通风四个主要技术单元,其中开拓运输技术采用多层环形水平道路结合上行和下行衔接坡道构建的相对独立的上行和下行道路；排水技术采取界外截水沟自流排放雨水和界内泵站分区和分级提升排放污水到顶部处理达标后再排放；边坡稳定采取土工格栅和生态袋的双重护坡技术；通风采取自然引导和人工强制通风相结合的技术。采用本发明的安全开采方法构建的安全高效的库区开拓运输道路,将存量垃圾从开采位置及时转运出来；进一步通过对排水、边坡稳定以及通风的改进,充分保障了填埋场开采作业的安全进行。(The invention discloses a safe mining method and a safe mining structure for a valley type domestic garbage landfill, and belongs to the field of solid waste resource utilization. The mining method comprises four main technical units of development transportation, drainage, slope stabilization and ventilation, wherein the development transportation technology adopts a multilayer annular horizontal road combined with an ascending and descending connection ramp to construct relatively independent ascending and descending roads; the drainage technology adopts an outside intercepting ditch to automatically drain rainwater and an inside pump station to divide areas and promote the drained sewage in a grading way to the top for treatment and then to be drained; the slope is stably protected by adopting a double slope protection technology of geogrids and ecological bags; the ventilation adopts the technology of combining natural guide and artificial forced ventilation. The safe and efficient reservoir area constructed by the safe mining method of the invention is used for developing a transportation road, and the stored garbage is timely transported out from the mining position; further, the safety of the mining operation of the landfill is fully guaranteed through improvement on drainage, slope stability and ventilation.)

1. A safe mining method for a valley type domestic garbage landfill is characterized in that the valley type domestic garbage landfill comprises the steps of mining by adopting a retreat-platform retracted excavation mode, wherein the retreat-platform retracted excavation mode is that a plurality of layers of annular roads are constructed layer by layer from outside to inside and from high to low, each layer of annular road is positioned on the same elevation plane, the diameters of the annular roads are gradually reduced layer by layer from top to bottom, and two adjacent annular roads are connected through a descending ramp and an ascending ramp respectively; the annular road is divided into an ascending section and a descending section, and the descending section of each layer of annular road and the descending ramp form a descending road; and the ascending section of each layer of annular road and the ascending ramp form an ascending road.

2. The method for safely mining a valley type domestic garbage landfill according to claim 1, wherein a step structure having a side slope is formed between adjacent annular roads, and a side slope angle α of the step structure is 30 to 45 °; and the slope angle beta of the connected ramp connecting the adjacent step roads is 10-15 degrees.

3. The method for safely exploiting the valley type domestic garbage landfill according to claim 2, wherein the annular roads and the ramps are constructed in a manner that a gravel road base is combined with a mesh plate reinforced composite plastic plate pavement.

4. The safe mining method for the valley type domestic garbage landfill according to claim 1, characterized in that the mining method further comprises a slope stabilizing step, and specifically comprises: and in the mining process, the slope is stabilized by adopting a double slope protection method of geogrids (240) and ecological bags (220) according to the annular road layering.

5. the safe mining method for the valley type domestic garbage landfill according to claim 4, wherein the slope stabilizing step is specifically: flattening and compacting a terrace, paving a geogrid (240), then pressing the geogrid (240) by using a plurality of ecological bags (220) and reserving the length of a turn-up bag, then, stacking the plurality of ecological bags (220) from low to high in a staggered manner layer by layer, and fixing the ecological bags (220) by the turn-up bag of the geogrid (240) after the ecological bags (220) are stacked to three layers; the ecological bags (220) are connected and fixed by adopting connecting buckles, and each layer of ecological bag (220) is tamped after being laid; after the geogrid (240) is reversely wrapped by the ecological bag (220), humus soil is backfilled between the ecological bag and the side slope and compacted to the same height of the top of the ecological bag (220); the above processes are repeated circularly until the design height of the side slope.

6. The safe mining method for the valley type domestic garbage landfill site according to the claim 1, characterized in that the mining method further comprises a drainage step, and the drainage step adopts a combined drainage scheme of diversion drainage of an outside intercepting ditch, water collection of an inside boundary area and gradual lifting and upward drainage of a pump station.

7. The method for safely exploiting the valley type domestic garbage landfill according to claim 6, wherein the draining step is specifically: arranging intercepting ditches around the stope according to the terrain; in the stope, along with the mining process, one side of the annular road is provided with a simple open drainage ditch (310) and a water collection well (320) with the gradient not less than 0.3% in a partition mode; when the mining depth exceeds 30 meters, grading pump stations are arranged on the edge of the annular road, water pumps among the grading pump stations perform relay drainage, and rainwater is pumped to a ground leachate treatment system by adopting a drainage mode of combining zone parallel connection and grading series connection.

8. the method for safely mining a valley type domestic garbage landfill according to claim 1, further comprising a ventilation step of combining a natural ventilation system and an artificially induced ventilation system; the natural ventilation system is characterized in that a splayed air guide wall (410) is arranged near a closed ring of the landfill site according to the perennial predominant wind direction of the position of the landfill site, a large opening of the air guide wall faces the perennial predominant wind direction, and a small opening of the air guide wall faces a pit so as to gather the earth surface wind current; meanwhile, according to the concentration of harmful gases and dust in the landfill, an artificial induction ventilation system is adopted, and an induction fan (430) is arranged in the induction ventilation system to strengthen the ventilation effect of the air intake of the natural ventilation system on the operation area.

9. The method for safely exploiting the valley type domestic garbage landfill according to claim 8, wherein the induction ventilation system is mainly composed of an air supply part, an induction ventilation part and an air exhaust part; wherein the air supply and exhaust part consists of an air supply fan (420) and an air exhaust fan (440), and is arranged on the ground close to the pithead at the top of the valley landfill; the induction fans (430) are arranged along the operation path and spirally blow wind at the lower part of the landfill to the upper part; the air supply fan (430), the exhaust fan (440) and the induction fan (430) adopt an intermittent working mode to ensure that the concentration of harmful gases or impurities in the atmosphere of the mining space is lower than 0.2-0.25 times of the allowable concentration.

10. a layered mining plane pit structure obtained by the mining method according to any one of claims 1 to 9.

Technical Field

the invention relates to the field of solid waste resource utilization, in particular to a safe mining method and a mining structure for a valley type domestic garbage landfill.

Background

About 2 hundred million tons of domestic garbage are generated in cities and towns of China every year, and more than 60 percent of domestic garbage are treated by adopting a landfill technology. In addition, the storage quantity of domestic garbage buried throughout the year exceeds 80 hundred million tons, the pollution situation is severe, a large amount of land is occupied, and meanwhile, the resource potential is huge. The 'urban mine' technology is used for safely exploiting, effectively sorting and classifying the stored household garbage for recycling, and has great practical significance for solving the problem of the household garbage. According to the difference of natural terrain conditions utilized by landfill areas, the domestic garbage landfill is roughly divided into 3 types: valley type landfill, plain type landfill and beach type landfill. According to terrain conditions, storage capacity conditions, design maturity conditions and the like, a landfill is preferably built in a valley in a common city. The valley type landfill has the advantages of large landfill capacity, low construction cost and the like, but because the valleys are mostly positioned at the upstream of the underground water, the pollution risk of the landfill to the underground water is a factor which needs to be considered seriously.

The technology for managing the stored garbage can be divided into two major categories, namely an in-situ repairing and sealing field adding technology and a safe mining and sorting ex-situ recycling technology. The in-situ restoration and sealing technology has less investment, can obviously reduce pollution load in a short time, forms park landscape and the like in situ through plant reclamation, but the garbage dump and the pollution restoration influencing the surrounding environment are not thorough enough, and the influence on the surrounding environment in the future is unknown. The ectopic resource technology is characterized in that all the garbage in the landfill body is safely exploited, classified resource utilization is carried out after effective separation, although the investment is large, the garbage heap body and pollution sources influencing the surrounding environment can be thoroughly eliminated, and meanwhile, the use value of the land can be released and improved.

The ex-situ resource technology needs to safely mine the garbage dump, and the conventional earthwork excavation technology is usually adopted for a plain or beach type landfill with shallow garbage burial depth and simple geological conditions at present, so that the mining technology is simple and the risk is low; for a valley type landfill, due to the fact that the landfill depth is large, the landform of a landfill area is complex, geological conditions are variable, no mature safety mining technology exists at present, and related technologies face a series of challenges:

(1) how to solve the problems of transportation organization, transportation road and the like after garbage mining. How to carry out efficient transportation organization, ensure safe operation and reduce transportation cost due to the transportation road frequently moving along with the mining working face? At present, the road construction of the refuse landfill mainly uses steel plate roadbed boxes to construct a temporary road, namely, a special clamp is adopted on the landfill operation site to clamp and connect the steel plate roadbed boxes in sequence to construct the temporary road for vehicles to pass through, and the surface of the temporary road adopts a pattern steel plate surface to prevent skidding. However, due to uneven settlement of garbage, gaps can be formed among the steel plate roadbed boxes after vehicles run, and the gaps are larger and larger, so that negative effects can be caused on the safety of field operation vehicles and personnel. And the environment of landfill site leads to the corruption aggravation of steel sheet roadbed case, and the steel sheet face is disorderly, all is debris between the flute on the steel sheet face for the frictional force of steel sheet face constantly reduces, also leads to the occurence of failure easily.

(2) How to effectively get rid of the filtration liquid that the rubbish layer produced and the sewage that surface runoff formed behind the precipitation in time, prevent that surface runoff from collecting and forming the destruction of flood to the operation special district, ensure the absolute safety in landfill exploitation operation area.

(3) how to guarantee the stability of the side slope in the deep pit mining operation process of the valley type landfill site so as to ensure the safety of transportation roads, vehicles and mining operation.

(4) The landfill gas (methane) of the valley type landfill is easy to gather and difficult to diffuse and dilute, and the safety risk of combustion and explosion is large; meanwhile, the problem of poor air quality of environment such as malodorous gas (such as ammonia gas, hydrogen sulfide, methyl mercaptan, methyl sulfide and the like) dust also exists, and the problem is not enough to solve the related problems by completely depending on natural ventilation.

In summary, the safe mining of valley type landfill sites currently requires the development of new safe mining techniques and methods that address the above issues.

disclosure of Invention

1. Technical problem to be solved by the invention

Aiming at the problems to be solved in the aspect of safe mining technologies such as exploitation and transportation of valley type refuse landfills, the invention provides a safe mining method of the valley type refuse landfills and a layered mining plane retreating platform deep pit structure, which ensure the safety of exploitation and transportation by a mining mode of constructing a transportation road through a multilayer annular exploitation road and further combining a gravel roadbed with a screen plate reinforced composite plastic plate road surface;

Further aiming at the problem of side slope stability of the mining structure, double slope protection of geogrids and ecological bags is adopted;

Further aiming at the problem of drainage during mining, the mining structure is combined to perform partition grading series connection to promote drainage;

Further aiming at the ventilation problem during mining, the system adopts the ventilation technology combining artificial reinforced natural ventilation and fan series induced ventilation, thereby efficiently realizing the safe mining of the valley type refuse landfill.

2. Technical scheme

In order to solve the problems, the technical scheme provided by the invention is as follows:

A safe mining method for a valley type domestic garbage landfill site is characterized in that when the sealing time of the mined landfill site is less than 6 years, the landfill gas generation amount is large, and the methane concentration is high (more than or equal to 5%), aerobic stabilization treatment is required to be firstly carried out to reduce the risk of combustion and explosion (the methane concentration is less than 5%) in the mining process, or when the sealing time of the landfill site is more than or equal to 6 years, the method for exploiting four aspects of transportation, drainage, slope stabilization, ventilation and the like is adopted for safe mining.

Aiming at the problem of safe exploitation and transportation of a landfill, the invention provides a safe exploitation method of a valley type domestic garbage landfill, aiming at the valley type domestic garbage landfill, the exploitation is carried out by adopting a retreat table retracting type excavation mode, the retreat table retracting type excavation mode is that a plurality of layers of annular roads are constructed layer by layer from outside to inside from high to low, each layer of annular road is positioned on the same elevation plane, the diameters of the annular roads are gradually reduced layer by layer from top to bottom, two adjacent annular roads are respectively connected through a descending ramp and an ascending ramp, the annular roads are divided into ascending sections and descending sections, and the descending sections of the annular roads of each layer and the descending ramp form a descending road; and the ascending section of each layer of annular road and the ascending ramp form an ascending road. In the mining process, when the garbage with the specific thickness is excavated, the retreating platform is retracted into the width of the transportation road, and then the garbage with the specific thickness is excavated downwards, so that the annular road on the same elevation plane is constructed layer by layer.

preferably, a step structure with a side slope is formed between adjacent annular roads, and the side slope angle alpha of the step structure is 30-45 degrees; and the slope angle beta of the connected ramp connecting the adjacent step roads is 10-15 degrees.

Preferably, the garbage transportation adopts a dump truck, and the total width b of the road at the same height (step) is 4-6m, and the height h of the step is 2-4 m.

Preferably, the annular road and the ramp are constructed in a mode of combining a gravel road base and a mesh plate reinforced composite plastic plate pavement. The broken stone roadbed is constructed by grading aggregate or grading backfill laying after crushing and screening construction waste, the maximum grain size is not more than 150mm, compaction is carried out after virtual laying, and the specific roadbed thickness is determined according to the field condition. The screen plate reinforced composite plastic board is produced by a regenerated plastic nonmetal alloy technology, is laid in a single layer, and is connected with adjacent pavement boards in a hot melting mode.

Preferably, in view of the slope stabilizing problem of the mining structure, the mining method further includes a slope stabilizing technique, specifically including: and in the mining process, adopting a double slope protection technology of geogrids and ecological bags according to the annular road in a layering manner to stabilize the side slope.

preferably, the terrace is flattened and compacted, then the geogrid is laid, then the geogrid is pressed by the ecological bag, the length of a reverse bag is reserved, then the ecological bag is staggered and laid layer by layer from low to high, and the bag body is laid on three layers and then fixed by the geogrid in a reverse bag manner; the ecological bag bodies are connected and fixed by adopting a connecting buckle, and each layer of ecological bag is tamped after being laid; after the geogrid is reversely wrapped with the ecological bag, humus soil is backfilled between the ecological bag and the side slope and compacted to the same height of the top of the ecological bag; the above processes are repeated circularly until the design height of the side slope; the top layer grating of the side slope can adopt a mode of tiling without turning up, and the top bag body is built according to super high base as a reserved settling volume. The ecological bag is sewn by polypropylene fiber or polyester fiber non-woven fabrics, and humus is filled in the ecological bag to ensure the water permeability of the ecological bag; the geogrid is made of glass fiber latticed structural materials.

Preferably, aiming at the problem of drainage during mining, in combination with the mining structure, the mining method further comprises a drainage technology, wherein the drainage technology adopts a combined drainage scheme of diversion drainage of an outside intercepting ditch, water collection of an inside intercepting ditch and gradual lifting and upward drainage of a pump station.

Preferably, the periphery of the stope is provided with intercepting ditches according to the terrain; in the stope, along with the mining process, one side of the annular road is provided with a simple open drainage ditch and a water collection well with the gradient not less than 0.3% in a partition mode; when the mining depth exceeds 30 meters, grading pump stations are arranged on the edge of the annular road, water pumps among the grading pump stations perform relay drainage, rainwater is pumped to a ground leachate treatment system by adopting a drainage mode of combining zone parallel connection and grading series connection, and the rainwater is discharged after reaching the standard after treatment. Arranging intercepting ditches around the stope according to the terrain, wherein the longitudinal slope is more than 3 percent, and the ditch bottom and the ditch side are paved by grouted rubbles to prevent leakage; in the stope, along with the mining process, more than 0.3 percent of longitudinal gradient drainage open ditches are regionally arranged on one side of each annular road plane close to the reservoir area side slope, rainwater on the road surface enters a water collecting well, and each water collecting well collects rainwater and sewage which oppositely flow in two directions to drain the open ditches; the width of the open drainage ditch is determined according to the service catchment area and the flow calculated by local meteorological hydrological parameters, and is usually not less than 0.5m, the initial depth of the open drainage ditch is 0.2m, and the end point depth of the open drainage ditch is not more than 1.7 m; arranging drainage lifting pumps in a water collecting well at the tail end of an open drain of the annular road, and when the mining depth exceeds 30m, adopting a mode of cascade relay drainage of the lifting pump stations in stages, wherein the lifting pumps in a plurality of water collecting wells work in a partition-parallel mode on the same road plane; and arranging a serial grading section at every 20m height, lifting the drainage of the lower serial grading section to the previous serial grading section water collecting tank through a submersible sewage pump, conveying the drainage to the previous stage through the submersible sewage pump in the previous serial grading section water collecting tank, and so on, lifting the collected drainage of each layer to a ground leachate treatment system finally, and discharging the drainage after the treatment reaches the standard.

preferably, further aiming at the ventilation problem during mining, the mining method also comprises a ventilation technology combining a natural ventilation system and an artificial induction ventilation system; the natural ventilation system is characterized in that a splayed air guide wall is arranged near a sealing ring of the landfill site according to the perennial predominant wind direction of the position of the landfill site, a large opening of the air guide wall faces the perennial predominant wind direction, and a small opening of the air guide wall faces a pit so as to gather the earth surface wind flow; meanwhile, according to the concentration of harmful gases and dust in the landfill, an artificial induction ventilation system is adopted, and an induction fan is arranged in the induction ventilation system to strengthen the ventilation effect of the air intake of the natural ventilation system on the operation area. The natural ventilation system and the artificial induced ventilation system are combined to enhance the gas guide and exhaust effect in the mining operation area.

Preferably, the induced ventilation system mainly comprises an air supply part, an induced ventilation part and an air exhaust part; wherein the air supply and exhaust part consists of an air supply fan, an air exhaust fan and a small amount of air pipes and is arranged on the ground close to the pithead at the top of the valley landfill; the induced fans are arranged along the operation path, the induced fans spirally blow wind at the lower part of the landfill to the upper part, and the air supply fans, the air exhaust fans and the induced fans all adopt an intermittent working mode according to the change of the concentration of polluted gas, dust and the like in the operation space of the landfill, so that the concentration of harmful gas or impurities in the atmosphere of the operation space of the landfill is ensured to be lower than 0.2-0.25 time of the allowable concentration.

A layered mining plane retreating platform deep pit structure obtained by the mining method.

3. advantageous effects

Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:

(1) According to the terrain characteristics of the valley-type landfill, an annular gradually-deepened mining and tunneling mode is adopted according to local conditions, so that a self-dumping truck can conveniently drive into the bottom of the landfill by utilizing an annular road to transport excavated garbage in time, and a descending channel and an ascending channel are completely separated, the problem that vehicles need to avoid each other is solved, and on the basis, a simple transportation road of a crushed stone base layer and a screen plate reinforced composite plastic plate is further constructed, so that the settlement of the road is prevented, and the transportation efficiency and the transportation safety are improved;

(2) In the invention, the side slope angle alpha of the step structure formed between adjacent annular roads is 30-45 degrees; the slope angle beta of a connecting ramp connecting adjacent step roads is 10-15 degrees, wherein the increasing of the slope angle of the step side is beneficial to improving the recovery rate of the landfill capacity, and the angle of the connecting ramp is relatively slow, so that the climbing of a load-carrying vehicle is facilitated and the driving safety is ensured;

(3) The double slope protection technology of the geogrid and the ecological bags is adopted, the characteristics of high strength, small deformation, good durability, ageing resistance and good water permeability of the ecological bags and the like of the geogrid are combined, an interlocking structure is formed among the ecological bags through the connecting buckles, the stability of the side slope of the valley type landfill and the driving safety of transport vehicles are effectively guaranteed, the construction is simple, the materials can be obtained locally, and the construction cost is low;

(4) The method of self-flow of the intercepting ditch outside the boundary, partition of the pumping station inside the boundary and forced upward discharge by the lifting of the graded water pump is adopted, so that the influence of rain sewage on the mining operation is reduced to the maximum extent, and the water discharge of the mining area and the scouring of rain water on the side slope are reduced;

(5) Natural guide ventilation is combined with jet flow induction artificial forced ventilation system in the mining pit through the air guide wall, so that the quality of air in the mining pit and the operation safety are guaranteed; the induction ventilation system does not need to be provided with an air pipe, the induction fan is convenient to install and move, and the induction ventilation system is particularly suitable for the application scene of continuous change of a mining working surface; the large-air-volume low-air-pressure type induction fan is selected, so that the power consumption of the equipment is low, and the investment and the operating cost are saved.

Drawings

FIG. 1 is a schematic view of the development transportation mode of the valley type landfill of the present invention;

FIG. 2 is a cross-sectional view of a planar deplaced deep pit structure of the present invention;

FIG. 3 is a schematic diagram of uplink and downlink paths in the present invention;

FIG. 4 is a schematic view of the double revetment of the present invention;

FIG. 5 is a schematic view of the graded drainage of the valley-type buried field according to the present invention;

FIG. 6 is a schematic view of the enhanced induced draft of the present invention;

in the figure: 100. a planar retreating platform pit structure; 110. a downlink section; 120. an ascending section; 130. side slope; 140. a descending ramp; 150. an ascending ramp; 160. the bottom of the landfill site;

200. A slope stabilizing structure; 210. a substrate; 220. an ecological bag; 230. a connecting buckle; 240. a geogrid; 241. a first geogrid layer; 242. a second layer of geogrid; 243. a third layer of geogrid; 250. backfilling;

300. A graded drainage structure; 310. draining the open ditch; 320. draining pump; 321. a primary draining pump; 322. a secondary drainage pump; 330. a water collecting well;

400. Strengthening the induced ventilation structure; 410. a wind guide wall; 420. an air supply fan; 430. an induction fan; 440. an exhaust fan.

Detailed Description

For a further understanding of the present invention, reference will now be made in detail to the embodiments illustrated in the drawings.