Gravel drainage layer backfill construction process for ensuring integrity of impermeable membrane

Abstract

The application discloses a pebble guide layer backfill construction process for guaranteeing the integrity of an anti-seepage film and relates to the technical field of building engineering. Technical points are as follows: the mechanical transformation is carried out in advance to avoid the damage of the anti-seepage film caused by the paving mechanical operation, the flow construction and the laying of a convenient path are adopted to avoid the direct action of the concentrated load of the pebble transport vehicle and the paving machine on the primary anti-seepage geomembrane, and the pebble transfer convenient path is built to effectively avoid the damage of the secondary anti-seepage film caused by the transfer vehicle, so that the damage of the lower anti-seepage material caused by the mechanical operation in the pebble guide layer laying process is solved, and the construction quality of the landfill anti-seepage material is improved.

Description

Technical Field

[0001] This invention relates to the technical field of building engineering, specifically to a pebble drainage layer backfilling construction process that ensures the integrity of the geomembrane. Background Technology

[0002] To prevent soluble components in hazardous waste from dissolving in water and gradually seeping out under the weight of the landfill, thus polluting the surrounding environment, secure landfills are lined at the bottom. Unlike landfills, secure landfills employ a double-layer artificial lining structure with higher-grade materials. Through multiple layers of various materials, hazardous waste is effectively isolated from the surrounding soil and groundwater. Furthermore, a leachate diversion layer within the lining is responsible for collecting leachate, which is then centrally treated to prevent pollution of groundwater and soil.

[0003] The aforementioned existing technical solutions have the following drawbacks: High-density polyethylene (HDPE) geomembrane is the most widely used impermeable material in landfills. During the construction of the gravel drainage layer on the membrane, mechanical transportation and paving operations are prone to creating damage and voids in the HDPE, making it difficult to control geomembrane damage. Compared to existing construction techniques, when backfilling gravel, transport vehicles directly drive onto the main impermeable membrane for backfilling or the paving machinery is not modified. When mechanically paving the gravel filter protection layer in landfills, improper mechanical operation can easily damage the geomembrane. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a gravel guide layer backfilling construction process that ensures the integrity of the geomembrane. Its advantages include: pre-modification of machinery to prevent damage to the geomembrane during paving operations; the use of continuous construction and temporary access roads to avoid direct impact of gravel transport vehicles and paving machinery loads on the primary geomembrane; and the construction of gravel transfer access roads to effectively prevent damage to the secondary geomembrane by transport vehicles. This solves the problem of mechanical operation damaging the underlying geomembrane during gravel guide layer laying, thereby improving the construction quality of landfill geomembranes.

[0005] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0006] A pebble drainage layer backfill construction process to ensure the integrity of the geomembrane. The geomembrane system adopts a double artificial liner layer for seepage prevention. The structure of the geomembrane layer from bottom to top is as follows: site foundation + 300mm thick crushed stone + 200g / m³ gravel. 2 Geotextile + 3000mm thick compacted clay + 750mm thick impermeable clay + 4.8kg / m 2Bentonite mat + 2.0mm secondary impermeable geomembrane + 6.3mm drainage net + 300mm thick clay impermeable layer + 2.0mm primary thick impermeable geomembrane + 600g / m 2 Geotextile + 5.2mm thick geonet + 300mm thick gravel + 200g / m 2 Geotextile.

[0007] In a preferred embodiment, the present invention may be further configured to include the following steps:

[0008] (1) Divide the construction sections: The pebble guide layer is paved in a segmented flow construction method;

[0009] (2) Preparation of pebble material: The particle size of the pebble material is selected and sharp stones are removed. The mud content is no more than 1%.

[0010] (3) Preparation of transfer and paving machinery: Small transport vehicles are used for transfer and small excavators are used for paving;

[0011] (4) Construction of access roads in the reservoir area: On a 300mm clay impermeable layer, a construction access road is constructed using a combination of geogrid drainage net, wooden formwork, and geogrid drainage net, totaling three layers.

[0012] (5) Pebble transportation: Small self-dumping transport vehicles are used for transportation. After being transported to the warehouse area, it is strictly forbidden to drive in areas other than the access road.

[0013] (6) Pebble paving: Excavators are used for paving. Small agricultural vehicles are used to transport pebbles to the completed primary seepage prevention system. Then, small excavators are used to transport the pebbles to the membrane. An 800mm thick pebble layer access road is built on the primary seepage prevention membrane. The excavator will go up to the pebble access road. On the access road, manual labor is used to help the excavator spread the pebbles. After the pebble paving is completed, the construction access road is dismantled as the project progresses.

[0014] In a preferred embodiment, the present invention can be further configured as follows: the excavator mentioned in step (3) above is a tracked excavator, the excavator track is equipped with track rubber block chain plates, and the excavator bucket uses steel plates with smooth edges and corners to weld and seal the bucket teeth.

[0015] In summary, the present invention has at least one of the following beneficial technical effects:

[0016] The machinery was modified in advance to avoid damage to the geomembrane during paving operations. The use of continuous construction and the laying of access roads prevented the concentrated loads of gravel transport vehicles and paving machinery from directly acting on the primary geomembrane. The construction of gravel transfer access roads effectively prevented damage to the secondary geomembrane by transfer vehicles. This solved the problem of damage to the underlying geomembrane caused by mechanical operations during the laying of the gravel guide layer and improved the construction quality of landfill geomembrane. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall process of the present invention;

[0018] Figure 2 This is a schematic diagram showing the connection between the excavator tracks and the rubber block chain plates;

[0019] Figure 3 This is a schematic diagram of the excavator bucket after processing.

[0020] Reference numerals: 1. Excavator track; 2. Rubber block chain plate; 3. Excavator bucket; 4. Steel plate. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings.

[0022] like Figure 1-3 As shown, this invention discloses a gravel drainage layer backfilling construction process to ensure the integrity of the geomembrane. The geomembrane system adopts a double artificial liner for seepage prevention. The structure of the geomembrane layer from bottom to top is as follows:

[0023] Site foundation;

[0024] 300mm thick crushed stone: The crushed stone here uses a particle size of 30-50mm;

[0025] 200g / m 2 Geotextile: The geotextile selected here is polypropylene woven geotextile, which, together with the aforementioned 300mm thick crushed stone, forms a groundwater drainage layer.

[0026] 3000mm thick compacted clay;

[0027] The advantage of 750mm thick impermeable clay and the aforementioned 3000mm thick compacted clay is that even if the HDPE membrane is accidentally damaged during operation, there is still a bottom last line of defense to provide better impermeability.

[0028] 4.8kg / m 2 Bentonite mat: GCL bentonite mats were selected here;

[0029] 2.0mm secondary geomembrane: Smooth HDPE secondary geomembrane is used here;

[0030] 6.3mm drainage net: Geocomposite drainage net is used here;

[0031] 300mm thick clay impermeable layer;

[0032] 2.0mm primary thickness geomembrane: Smooth HDPE primary geomembrane is used here;

[0033] 600g / m2 Geotextile: Polyester nonwoven geotextile is used here;

[0034] 5.2mm thick geogrid drainage net;

[0035] 300mm thick gravel layer: The gravel here uses 30-50mm particle size and is used as a leachate drainage layer.

[0036] 200g / m 2 Geotextile: Polypropylene woven geotextile is selected here.

[0037] The specific construction process is as follows, including the following steps:

[0038] (1) Dividing the construction sections: The pebble drainage layer is laid in a segmented flow construction method; this can avoid the transport vehicles directly contacting the primary geomembrane during the pebble transportation and paving process. Since the primary geomembrane only has 600g / m2 polyester non-woven geotextile and 5.2mm thick composite geodrainage net, the protection of the primary geomembrane is limited. The segmented flow construction method is adopted, that is, after laying a section of 2.0mm thick smooth HDPE primary geomembrane + 600g / m2 polyester non-woven geotextile + 5.2mm thick composite geodrainage net, the pebble drainage layer is backfilled. This can avoid the concentrated load generated by the tires of the transport vehicles on the primary geomembrane and damage to the geomembrane.

[0039] (2) Preparation of pebble material: The pebble material is screened by particle size, and sharp stones in the pebble material are removed. The mud content is not more than 1%. The particle size of the pebble material is controlled at 30-50mm. Pebbles that do not meet the particle size requirements need to be screened. If the pebble particle size is too small, it will easily cause compression damage to the geomembrane under the pebble. If the particle size is too large, it will easily cause coarse particles to concentrate and become hollow.

[0040] (3) Preparation of Transfer and Paving Machinery: Small transport vehicles will be used for transfer, and small excavators will be used for paving. The gravel usually arrives at the construction site in large transport vehicles, which are too heavy to be transported directly to the bottom of the silo. Small transport vehicles with a load capacity of 2T will be used for transfer. The weight limit for machinery and equipment in the silo area is 6T. A 60-type excavator will be used for paving. The excavator should be a tracked excavator with rubber track pads and chain plates. Figure 2 As shown, this design avoids damage to the geomembrane caused by track wear due to operational errors. The excavator bucket uses smooth-edged steel plates to weld and seal the bucket teeth, such as... Figure 3 As shown, during the gravel paving process, the efficiency of gravel leveling can be improved, and damage to the geomembrane caused by improper operation of the excavator bucket teeth can also be prevented.

[0041] (4) Construction of access roads in the reservoir area: On the 300mm clay impermeable layer, a construction access road is constructed in three layers: geogrid drainage net + wooden formwork + geogrid drainage net. This is used to transport gravel materials and protect the secondary impermeable system that has been completed below. The wooden formwork can distribute the concentrated load of vehicle tires and prevent the concentrated load of vehicles from damaging the secondary impermeable membrane of the 300mm clay layer during transportation.

[0042] (5) Gravel Transfer: Small self-dumping transport vehicles shall be used for transfer. After arriving at the storage area, vehicles are strictly prohibited from driving outside the access road. The weight limit of the vehicle during the transfer process is 6T, and the load of pebbles on the vehicle shall not exceed the sideboards of the vehicle cargo box to prevent a large number of pebbles from scattering when driving on the access road. The transfer vehicle is strictly prohibited from driving on the primary geomembrane. Self-unloading shall be carried out on the access road. Any pebbles scattered during the process shall be cleaned up manually in a timely manner to prevent the pebbles from being crushed by the vehicle and causing damage to the geomembrane.

[0043] (6) Pebble paving: Excavators are used for paving. Small agricultural vehicles are used to transport pebbles to the completed primary seepage prevention system. Then, small excavators are used to transport the pebbles to the membrane. An 800mm thick pebble layer access road is built on the primary seepage prevention membrane. The excavator will go up to the pebble access road. On the access road, manual labor is used to help the excavator spread the pebbles. After the pebble paving is completed, the construction access road is dismantled as the project progresses.

[0044] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A construction process for backfilling a pebble drainage layer to ensure the integrity of the geomembrane, characterized in that, The seepage prevention system adopts a double artificial lining layer. The structure of the seepage prevention layer from bottom to top is as follows: site foundation + 300mm thick crushed stone + 200g / m³ 2 Geotextile + 3000mm thick compacted clay + 750mm thick impermeable clay + 4.8kg / m 2 Bentonite mat + 2.0mm secondary impermeable geomembrane + 6.3mm drainage net + 300mm thick clay impermeable layer + 2.0mm primary thick impermeable geomembrane + 600g / m 2 Geotextile + 5.2mm thick geonet + 300mm thick gravel + 200g / m 2 Geotextile; On the 300mm thick clay impermeable layer, a construction access road is constructed using a combination of geogrid drainage net, wooden formwork, and geogrid drainage net, totaling three layers. After laying the 2.0mm primary thickness impermeable geomembrane, 600g / m² geotextile, and 5.2mm thick geogrid drainage net, an 800mm thick pebble layer access road is constructed on the 2.0mm primary thickness impermeable geomembrane. An excavator is then deployed to the pebble layer access road, where manual labor is used in conjunction with the excavator to spread the 300mm thick pebbles. Once the pebble layer is laid, the construction access road is dismantled as the project progresses. The pebble guide layer is laid in a segmented, continuous construction manner; small dump trucks are used for transportation, and after being lowered into the storage area, they are strictly prohibited from driving in areas other than the access road; the excavator is a tracked excavator, with track rubber blocks and chain plates added to the excavator tracks, and the excavator bucket has its teeth welded and sealed with steel plates with smooth edges.

2. The gravel drainage layer backfilling construction process for ensuring the integrity of the geomembrane according to claim 1, characterized in that, Includes the following steps: (1) Divide the construction sections: The pebble guide layer is paved in a segmented flow construction method; (2) Preparation of pebble material: The pebble material is screened by particle size, and sharp stones are removed from the pebble material. The mud content is not more than 1%; (3) Preparation of transfer and paving machinery: Small transport vehicles are used for transfer, and small excavators are used for paving; (4) Construction of access roads in the reservoir area: On a 300mm clay impermeable layer, a construction access road is constructed using a combination of geogrid drainage net, wooden formwork, and geogrid drainage net, totaling three layers. (5) Pebble transportation: Small self-dumping transport vehicles are used for transportation. After arriving at the warehouse area, it is strictly forbidden to drive in areas other than the access road. (6) Pebble paving: Excavators are used for paving. Small agricultural vehicles are used to transport pebbles to the completed primary seepage prevention system. Then, small excavators are used to transport the pebbles to the membrane. An 800mm thick pebble layer access road is built on the primary seepage prevention membrane. The excavator will go up to the pebble access road. On the access road, manual labor is used to help the excavator spread the pebbles. After the pebble paving is completed, the construction access road is dismantled as the progress is made.

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