胶接法拼接和焊接法是土工膜应用初期常用的两种拼接方法

受(shou)土(tu)工(gong)(gong)(gong)膜(mo)生(sheng)产工(gong)(gong)(gong)艺影响,出厂制品幅宽(kuan)不能(neng)满(man)足(zu)库盘和(he)(he)坝面宽(kuan)度(du)需求,现场拼接(jie)(jie)是(shi)解决问(wen)题的(de)(de)主要(yao)技术(shu)(shu)手段,拼接(jie)(jie)质(zhi)量(liang)关乎工(gong)(gong)(gong)程(cheng)(cheng)的(de)(de)成(cheng)败。胶(jiao)接(jie)(jie)法(fa)和(he)(he)焊(han)接(jie)(jie)法(fa)是(shi)土(tu)工(gong)(gong)(gong)膜(mo)应用(yong)初期常用(yong)的(de)(de)两种拼接(jie)(jie)方(fang)(fang)法(fa),对PE和(he)(he)PVC膜(mo)的(de)(de)粘接(jie)(jie)方(fang)(fang)法(fa)进(jin)(jin)行较为深(shen)入细致的(de)(de)研究,并改(gai)进(jin)(jin)了两种土(tu)工(gong)(gong)(gong)膜(mo)的(de)(de)拼接(jie)(jie)技术(shu)(shu)及施工(gong)(gong)(gong)工(gong)(gong)(gong)艺;后(hou)期因限于(yu)化工(gong)(gong)(gong)技术(shu)(shu)水平和(he)(he)施工(gong)(gong)(gong)技术(shu)(shu)不精细等(deng)因素,胶(jiao)接(jie)(jie)法(fa)逐渐被(bei)弃用(yong),随着热焊(han)机(ji)等(deng)焊(han)接(jie)(jie)设备的(de)(de)不断改(gai)进(jin)(jin),焊(han)接(jie)(jie)法(fa)成(cheng)为土(tu)工(gong)(gong)(gong)膜(mo)拼接(jie)(jie)的(de)(de)主要(yao)方(fang)(fang)法(fa);虽然焊(han)接(jie)(jie)法(fa)被(bei)推广应用(yong),但焊(han)接(jie)(jie)质(zhi)量(liang)受(shou)焊(han)接(jie)(jie)温度(du)、焊(han)机(ji)行进(jin)(jin)速(su)度(du)和(he)(he)土(tu)工(gong)(gong)(gong)膜(mo)厚度(du)等(deng)因素影响,易(yi)造成(cheng)焊(han)缝处及其周边土(tu)工(gong)(gong)(gong)膜(mo)热力(li)(li)学损伤,物(wu)理力(li)(li)学性能(neng)衰减,如南水北调中(zhong)线干渠0.3mm厚PE焊(han)接(jie)(jie)复(fu)合土(tu)工(gong)(gong)(gong)膜(mo),接(jie)(jie)缝拉(la)伸(shen)断裂强度(du)仅为母材强度(du)的(de)(de)27%;土(tu)工(gong)(gong)(gong)膜(mo)的(de)(de)缺(que)陷更多产生(sheng)在(zai)施工(gong)(gong)(gong)过程(cheng)(cheng),主要(yao)是(shi)土(tu)工(gong)(gong)(gong)膜(mo)拼接(jie)(jie)时脱(tuo)焊(han)、虚焊(han)等(deng)导致的(de)(de)缝状缺(que)陷,以及施工(gong)(gong)(gong)人(ren)员或施工(gong)(gong)(gong)机(ji)械引起土(tu)工(gong)(gong)(gong)膜(mo)顶破和(he)(he)刺破的(de)(de)孔洞等(deng)。

一般HDPE膜(mo)硬度偏大,但膜(mo)厚度不大于0.5mm仍具(ju)有柔韧性(xing)(xing),因具(ju)有较好的(de)抗(kang)化学腐蚀性(xing)(xing)能(neng),在(zai)垃圾(ji)填埋场(chang)防(fang)渗结构(gou)中广泛应(ying)用(yong),随(sui)着施工(gong)(gong)设备与施工(gong)(gong)技术的(de)日臻成熟(shu)和市(shi)场(chang)推广,HDPE土工(gong)(gong)膜(mo)在(zai)部分水利工(gong)(gong)程库盘防(fang)渗和平原区蓄水池等堤坝上得到(dao)应(ying)用(yong)。为(wei)(wei)解(jie)决HDPE膜(mo)缺陷性(xing)(xing)渗漏问(wen)题,国内研(yan)发(fa)了一种(zhong)HDPE土工(gong)(gong)膜(mo)专用(yong)胶(jiao)(jiao),选用(yong)胶(jiao)(jiao)接(jie)法(fa)修(xiu)补(bu)施工(gong)(gong)过程中因颗(ke)粒垫层(ceng)顶胀破(po)(po)坏,避免焊接(jie)施工(gong)(gong)造成膜(mo)力(li)学性(xing)(xing)能(neng)损伤,为(wei)(wei)揭(jie)示此类胶(jiao)(jiao)接(jie)法(fa)的(de)水力(li)性(xing)(xing)能(neng),胶(jiao)(jiao)接(jie)法(fa)拼接(jie)和修(xiu)补(bu)顶胀破(po)(po)损土工(gong)(gong)膜(mo)方法(fa)的(de)防(fang)渗效果(guo),展(zhan)开耐静水压的(de)试验性(xing)(xing)研(yan)究。