阅读说明：本技术 一种用于垃圾填埋场hdpe土工膜的焊接及检测工艺 (Welding and detection process for HDPE (high-density polyethylene) geomembrane of refuse landfill ) 是由 万学林 张玉柱 王伟 石真明 王利文 滕志明 佟国锋 于 2020-04-13 设计创作，主要内容包括：本发明公开了一种用于垃圾填埋场HDPE土工膜的焊接及检测工艺,焊接工艺中的焊接设备包括双缝焊接机、挤压焊机和热吹风机,以双缝焊接为主,打压封口、接缝或局部修补采用挤压焊机做挤压焊缝,搭接部位下方用热吹风机吹熔；检测工艺以气压检测为主,配合真空检测,适用于局部按幅推进或要求焊缝全检的情况,气压检测与真空检测均依据CJJ113-2007标准。本发明包括焊接施工及检测的施工工艺,在局部焊缝需全检施工或要求按幅推进的情况下,能充分发挥焊接机作用,减少挤压焊修补工作,简化焊缝检测流程,提高施工效率,能满足垃圾填埋场防渗和长期运营的需求。(The invention discloses a welding and detection process for HDPE geomembranes in refuse landfills, wherein welding equipment in the welding process comprises a double-seam welding machine, an extrusion welding machine and a hot air blower, wherein the double-seam welding is mainly adopted, the extrusion welding machine is adopted for pressing and sealing, seams or local repair, and the hot air blower is used for blowing and melting the lower part of a lap joint part; the detection process is mainly based on air pressure detection and matched with vacuum detection, is suitable for the conditions of local amplitude advance or required weld joint full detection, and is based on CJJ113-2007 standard for both air pressure detection and vacuum detection. The construction process comprises welding construction and detection, can fully play the role of a welding machine under the condition that local welding seams need to be constructed in a full-inspection mode or pushed according to the width, reduces extrusion welding repair work, simplifies a welding seam detection process, improves the construction efficiency, and can meet the requirements of landfill seepage prevention and long-term operation.)

1. A welding and detection process for HDPE geomembranes of refuse landfills is characterized in that:

the welding equipment in the welding process comprises a double-seam welding machine, an extrusion welding machine and a hot air blower, wherein double-seam welding is mainly adopted, extrusion welding seams are formed by pressing and sealing, seams or local repair, the extrusion welding machine is adopted for extrusion welding seams, the hot air blower is used for blowing and melting the lower part of the overlapped part, a hot air welding seam is formed after overlapping, then the hot air welding seam and the outer side of the HDPE geomembrane are repaired by using a hot melting welding strip of the extrusion welding machine, an extrusion material and the hot air welding seam jointly form the extrusion welding seams, the HDPE geomembrane above the air channel in the double-seam welding is buckled by a knife at the local position, the air channel is filled with the extrusion material of the extrusion welding machine, and a seal;

the detection process is mainly based on air pressure detection, is matched with vacuum detection, is suitable for the conditions of local amplitude pushing or required weld joint full detection, and is based on CJJ113-2007 standard, and the air pressure detection process comprises the following steps: after two ends of the double-track welding seam air cavity are plugged, pressurizing the welding seam air cavity to 250kPa by using gas detection equipment, and keeping the pressure for 3-5min, wherein the pressure is not lower than 240 kPa; the vacuum detection process comprises the following steps: the extrusion welding forms a single-rail welding seam, negative pressure is applied to a to-be-detected part through vacuum detection equipment, and when air pressure reaches 25-35 kPa, the welding seam does not leak.

2. The welding and detection process for HDPE geomembrane for refuse landfill according to claim 1, characterized in that: when the welding process is implemented, welding is laid by taking each frame as a unit, detection is carried out immediately after welding is finished, and flow operation can be formed for construction when welding is divided according to areas.

3. The welding and detection process for HDPE geomembrane for refuse landfill according to claim 1, characterized in that: the HDPE geomembrane connecting part forms 2T-shaped interfaces, all possible leakage parts of the joint interface are basically covered in a double-seam welding air pressure detection mode, and the positions of the two T-shaped interfaces can be respectively detected by adopting a vacuum detection method.

4. The welding and detection process for HDPE geomembrane for refuse landfill according to claim 1, characterized in that: the atmospheric pressure detects the extrusion welding seam and seals the position, and the width should be greater than the air flue width is scratched to the knife to guarantee the leakproofness sealed.

Technical Field

The invention relates to the technical field of HDPE geomembrane welding construction, in particular to a welding and detecting process for HDPE geomembranes in refuse landfills.

Background

In the welding construction of HDPE geomembranes in refuse landfills, the HDPE geomembrane is one of the most main impermeable layers, and the problem of environmental pollution caused by infiltration of landfill leachate can be solved, and HDPE geomembrane welding nodes are main weak points, so that HDPE geomembrane welding is the key point of impermeable design and quality control. As shown in fig. 2, a conventional joint for welding HDPE geomembranes is formed by using a conventional HDPE geomembrane welding method in a mode of mainly double seam welding and extrusion welding repair. However, in the traditional method, a system is not formed, so that more welding seams and interfaces or areas for vacuum detection are increased, a large amount of detection work is increased under the condition of full detection, progress and detection integrity are influenced, and certain hidden danger exists.

For two traditional HDPE geomembrane welding modes shown in figures 1 and 2, the welding process does not strictly require the welding seam position, the welding seam position has deviation in the construction process, the welding seam interface position is easy to deviate or even miss, and then the welding seam is covered or embedded in a patch mode and then extruded. The method not only increases the construction process, potential leakage points and the length of the welding line, but also is difficult to ensure the engineering quality, especially the T-shaped interface position.

Disclosure of Invention

In order to overcome the technical defects that the welding quality of HDPE geomembranes of the refuse landfill is difficult to guarantee, the detection workload after welding is large and the like in the prior art, the invention provides a welding and detection process for HDPE geomembranes of the refuse landfill, which reduces the number of welding seams, simplifies and models the detection process, improves the construction efficiency under the condition of full inspection, is matched with the later method to insert flow operation, simultaneously meets the detection requirement of the HDPE geomembrane, ensures the welding quality and solves the technical problems.

The invention achieves the aim through the following technical scheme, and the welding and detection process for the HDPE geomembrane in the refuse landfill adopts a mode of mainly double-seam welding and extrusion welding repair. The transverse welding seams are unified in the laying direction, so that the welding seams are simplified, and meanwhile, the detection process is reduced. The HDPE geomembrane is overlapped above the former method in the subsequent method in the laying direction so as to simplify the construction process, and the upper layer covers the lower layer in the slope direction so as to reduce the possibility that percolate enters a weld gap in the slope direction. The center distance between two vertical welding lines vertical to the laying direction is not less than 500 mm.

The top layer HDPE geomembrane air flue position is scratched to open by a knife in the air pressure detection extrusion welding seal opening position, extrusion welding is adopted to conduct extrusion welding seal opening treatment, the blocking of the end in the air flue is guaranteed, and pressing operation can be conducted. And each HDPE geomembrane laying can detect the anti-seepage effect of one HDPE geomembrane (vertical to the laying direction) at a time, so that the influence of detection on the on-site laying progress is greatly reduced. Form "T" style of calligraphy interface node position, exist three-layer HDPE geomembrane in vertical, form the perpendicular handing-over of twice welding seam, do local excision processing to the non-welding seam outside position of preceding one welding double-deck HDPE geomembrane position, slope is cut to the interface, and is mild excessive, avoids appearing the tip gas pocket, forms the leakage point. During construction, the advancing speed of the double-seam welding machine is slowed down at the position, the welding seam penetration of the interface position is ensured, and no gap is left.

According to the welding and detection process for the HDPE geomembrane for the refuse landfill, 2T-shaped interfaces are formed at the joint parts of the four HDPE geomembranes, all possible leakage parts of the joint interfaces are basically covered in a double-seam welding air pressure detection mode, and if the effect of extruding welding seams is worried, a vacuum detection method can be adopted to respectively detect the two T-shaped interfaces.

The welding and detection process for the HDPE geomembrane of the refuse landfill comprises the steps of detecting the position of an extrusion welding seal opening by air pressure, and slightly increasing the opening width of a knife to ensure the sealing tightness of the seal opening.

According to the welding and detection process for the HDPE geomembrane in the refuse landfill, the double-seam welding part of the machine in the laying direction is continuously welded along the original welding seam position, so that the potential leakage hazard is prevented from being misplaced and increased, and the extrusion welding seam is increased at the periphery if necessary.

Generally, compared with the prior art, the technical scheme of the invention can achieve the following beneficial effects: the welding and detection process for the HDPE geomembrane of the refuse landfill adopts the existing welding mode and detection method, and the process flows of all parts are not changed except the lap joint mode, the construction sequence and the position in the construction process, so that the operation is simple for relatively experienced workers, the operation is easy to operate, the number of welding seams and detection are reduced integrally, the construction quality can be ensured, the full detection efficiency is improved by optimizing the construction and detection process, and the HDPE geomembrane is convenient to insert into streamlined construction operation.

Drawings

The following detailed description of embodiments of the invention is provided in conjunction with the appended drawings, in which:

fig. 1 is a schematic view of a first conventional HDPE geomembrane welding and detection process;

fig. 2 is a schematic view of a second conventional HDPE geomembrane welding and inspection process;

FIG. 3 is a schematic view of a welding and inspection process for HDPE geomembranes of a refuse landfill according to the present invention;

FIG. 4 is a weld seam schematic of a double seam weld;

FIG. 5 is a schematic view of a compression welded seam.

Detailed Description

As shown in fig. 3, a schematic diagram of a welding and detection process for HDPE geomembranes in a refuse landfill according to the present invention is shown, taking a common node for welding 4 HDPE geomembranes as an example, dividing into four ABCD geomembranes for joining, constructing 1,2,3,4 for four double seams in total, correspondingly forming four compressible air passages, 5,6,7 for 3 sealing extrusion welding seams, wherein the laying direction is from right to left, the slope direction is from top to bottom, and the BD two HDPE geomembranes are already laid and overlapped when the node is constructed. When the HDPE geomembranes are arranged, the overlapped up-and-down sequence of the HDPE geomembranes requires that the upper layer in the gradient direction covers the lower layer, the back layer in the laying direction covers the front layer, and the sequence of the vertically upper HDPE geomembranes from top to bottom is A → B → C → D.

The construction sequence of the welding seam is as follows: 1 → 2 → 3 → 4, wherein the welding seams 1 and 7 are already completed welding seams during previous BD construction, the air pressure detection of the air passage of the welding seam 1 is already completed in the previous construction, and the four air passages are formed in the sequence from top to bottom: 2 → 4, 1 → 3.

In the using process, the welding and detection process is carried out according to the following steps:

the method comprises the following steps: confirming that the detection procedures such as HDPE geomembrane pressure detection (including 1 air passage) and the like where the BD is located are completed, wherein the distance between the No. 7 sealing extrusion welding seam position and the edge of the D film is about 10cm, and controlling the normal advance of welding equipment and the position as close to an actual fusion welding seam as possible according to the condition of double-seam welding equipment;

step two: laying AC two HDPE geomembranes, enabling the positions of 1 and 4 welding seams to be positioned on a straight line by means of local cutting of an A film and the like, sequentially welding 3 double seams of 2,3 and 4, welding 2 and 3 welding seams from top to bottom, and welding 4 welding seams from right to left in a receded manner so that the welding seams are complete and double seam welding equipment is smoothly taken out, aligning the welding seam 1 during welding, and ensuring the air passage to be closed, wherein the welding seam is a schematic diagram of the welding seams of double seam welding as shown in figure 4;

step three: sealing the welding seam air passage by using extrusion welding, wherein the positions of the left sides of the welding seams are No. 7 positions corresponding to the welding seam 1 of 5,6 and 4 respectively, the total number of the positions is three, and the knife opening width of the sealing position is larger than the width of the air passage so as to ensure tight sealing, and the sealing position is a schematic view of the welding seam of the extrusion welding as shown in figure 5;

step four: and (3) carrying out air pressure detection on the air passages 2,3 and 4, carrying out vacuum detection on three crossed T-shaped interfaces of the BCD, starting the next process when the detection reaches the standard, and repeatedly detecting after searching for leakage points and carrying out extrusion repair when the detection does not reach the standard.

The laying direction and the sloping direction can be spatially adjusted according to actual conditions, and are not limited to the positional relationship shown in the drawings.

The HDPE geomembrane welding and detecting process is optimized, the process is simplified, the operation is easy, and meanwhile, the welding and detecting process is standardized, so that the welding seam quality is favorably controlled. In consideration of welding and detection processes of the HDPE geomembrane, the welding of the HDPE geomembrane is more standard and reliable, the requirements of seepage-proofing effect and detection are met, the process is simplified, and the construction efficiency is improved.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.