土工膜的(de)特征是什么，材料(liao)有(you)何(he)特點？土工膜的(de)特征是什么，材料(liao)有(you)何(he)特點？

        土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)是(shi)(shi)一(yi)種(zhong)以高分子(zi)聚(ju)合(he)(he)物為(wei)(wei)基本原料(liao)(liao)的(de)防水(shui)阻隔型材料(liao)(liao)。主要分為(wei)(wei)密度(du)(du)低(di)的(de)聚(ju)乙烯（LDPE）土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)、高密度(du)(du)聚(ju)乙烯（HDPE）土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)和EVA土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)。經(jing)(jing)編(bian)(bian)(bian)復(fu)合(he)(he)土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)不同于(yu)一(yi)般土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)。其特(te)點(dian)是(shi)(shi)經(jing)(jing)線與(yu)緯線的(de)交(jiao)叉(cha)點(dian)不彎(wan)曲，各自(zi)處(chu)于(yu)平直狀態。用(yong)編(bian)(bian)(bian)織(zhi)線將兩(liang)者(zhe)(zhe)捆扎牢固，可(ke)較(jiao)均勻同步，承受(shou)外(wai)力，分布應(ying)力，且當施加(jia)的(de)外(wai)力撕(si)(si)裂材料(liao)(liao)的(de)瞬(shun)時，紗線會沿初(chu)裂口(kou)擁集，增(zeng)加(jia)抗(kang)撕(si)(si)裂強(qiang)(qiang)度(du)(du)。經(jing)(jing)編(bian)(bian)(bian)復(fu)合(he)(he)時，即利用(yong)經(jing)(jing)編(bian)(bian)(bian)織(zhi)線在(zai)經(jing)(jing)，緯紗與(yu)土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)的(de)纖維層間反復(fu)穿(chuan)行，使三者(zhe)(zhe)編(bian)(bian)(bian)結為(wei)(wei)一(yi)體。因(yin)而經(jing)(jing)編(bian)(bian)(bian)復(fu)合(he)(he)土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)既具有(you)(you)高抗(kang)拉強(qiang)(qiang)度(du)(du)，低(di)延伸率的(de)特(te)點(dian)，又兼有(you)(you)土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)的(de)防水(shui)性(xing)能。因(yin)此經(jing)(jing)編(bian)(bian)(bian)復(fu)合(he)(he)土(tu)(tu)(tu)(tu)工(gong)膜(mo)(mo)是(shi)(shi)一(yi)種(zhong)具在(zai)加(jia)筋增(zeng)強(qiang)(qiang)、隔離、防護(hu)作用(yong)的(de)防滲材料(liao)(liao)。它是(shi)(shi)當今國際上(shang)高水(shui)平的(de)應(ying)用(yong)土(tu)(tu)(tu)(tu)工(gong)復(fu)合(he)(he)材料(liao)(liao)。

高(gao) 抗拉強(qiang)度(du)(du)，低延伸率，縱橫向變形(xing)均勻，抗撕裂強(qiang)度(du)(du)高(gao)，耐(nai)磨性(xing)能(neng)優良(liang)，隔水性(xing)強(qiang)。。復(fu)合土工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)以塑料(liao)(liao)薄膜(mo)(mo)(mo)(mo)(mo)作為(wei)(wei)防(fang)滲(shen)基材，與(yu)無紡布復(fu)合而(er)成的(de)(de)土工(gong)(gong)防(fang)滲(shen)材料(liao)(liao)，它(ta)的(de)(de)防(fang)滲(shen)性(xing)能(neng)主要(yao)取決(jue)于塑料(liao)(liao)薄膜(mo)(mo)(mo)(mo)(mo)的(de)(de)防(fang)滲(shen)性(xing)能(neng)。國(guo)內外(wai)防(fang)滲(shen)應用(yong)(yong)的(de)(de)塑料(liao)(liao)薄膜(mo)(mo)(mo)(mo)(mo)，主要(yao)有(PVC)聚乙(yi)烯(xi)(xi)（PE）、乙(yi)烯(xi)(xi)/醋酸乙(yi)烯(xi)(xi)共聚物(wu)（EVA)，它(ta)們是(shi)一種高(gao)分子化學柔性(xing)材料(liao)(liao)，比重較(jiao)小，延伸性(xing)較(jiao)強(qiang)，適應變形(xing)能(neng)力高(gao)，耐(nai)腐蝕，耐(nai)低溫，抗凍性(xing)能(neng)好。復(fu)合土工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)的(de)(de)使用(yong)(yong)年(nian)(nian)(nian)(nian)限(xian)(xian)(xian)(xian)問題(ti)，主要(yao)是(shi)由(you)塑料(liao)(liao)薄膜(mo)(mo)(mo)(mo)(mo)是(shi)否失去防(fang)滲(shen)隔水作用(yong)(yong)而(er)定，據蘇聯國(guo)家(jia)標準(zhun)規定，水工(gong)(gong)用(yong)(yong)的(de)(de)厚度(du)(du)為(wei)(wei)0.2m的(de)(de)加穩定劑的(de)(de)聚乙(yi)烯(xi)(xi)薄膜(mo)(mo)(mo)(mo)(mo)，在(zai)清水條件下(xia)工(gong)(gong)作年(nian)(nian)(nian)(nian)限(xian)(xian)(xian)(xian)可(ke)達40~50年(nian)(nian)(nian)(nian)，在(zai)污水條件下(xia)工(gong)(gong)作年(nian)(nian)(nian)(nian)限(xian)(xian)(xian)(xian)為(wei)(wei)30~40年(nian)(nian)(nian)(nian)。因(yin)此(ci)復(fu)合土工(gong)(gong)膜(mo)(mo)(mo)(mo)(mo)的(de)(de)使用(yong)(yong)年(nian)(nian)(nian)(nian)限(xian)(xian)(xian)(xian)足以滿足大(da)壩防(fang)滲(shen)要(yao)求的(de)(de)使用(yong)(yong)年(nian)(nian)(nian)(nian)限(xian)(xian)(xian)(xian)。