采用土工布作坝体反滤的工程效果
土(tu)(tu)工布作为(wei)(wei)一种新型过滤材料,用(yong)(yong)(yong)(yong)于(yu)坝体(ti)的(de)反(fan)滤结(jie)构中,其(qi)主要作用(yong)(yong)(yong)(yong)是防止受保(bao)护土(tu)(tu)体(ti)被(bei)冲蚀(shi)透水(shui)和保(bao)砂作用(yong)(yong)(yong)(yong),是导致(zhi)坝体(ti)决口、溃坝的(de)主要原因。为(wei)(wei)使土(tu)(tu)工布更有效地发(fa)(fa)挥其(qi)作用(yong)(yong)(yong)(yong),并保(bao)证施工质(zhi)量,应采(cai)用(yong)(yong)(yong)(yong)“先立干砌石,后挂土(tu)(tu)工布,后接(jie)填土(tu)(tu)”的(de)施工工艺(yi)。本(ben)发(fa)(fa)明既能有效地控制各层的(de)施工,又能保(bao)证土(tu)(tu)工布的(de)铺(pu)设质(zhi)量。
(1)土工(gong)作(zuo)业要比山皮(pi)石(shi)施工(gong)效果好。山皮(pi)石(shi)作(zuo)为传统的(de)反(fan)滤层(ceng),其(qi)(qi)突出(chu)问题(ti)是施工(gong)质量得不到保证,尤其(qi)(qi)是含沙(sha)(sha)量较(jiao)高的(de)山皮(pi)石(shi),在海潮冲刷下(xia)流时,往(wang)往(wang)会(hui)出(chu)现塌方和裂缝(feng),泥沙(sha)(sha)一旦挤入石(shi)块的(de)缝(feng)隙,堵塞排(pai)水(shui)(shui)通道,会(hui)产(chan)生孔隙水(shui)(shui)压力,对石(shi)堤极(ji)为不利,增(zeng)大了(le)石(shi)堤的(de)倾覆力矩(ju)。用(yong)土布作(zuo)反(fan)滤层(ceng),利用(yong)其(qi)(qi)滤砂排(pai)水(shui)(shui)的(de)作(zuo)用(yong),彻底(di)解决了(le)山皮(pi)石(shi)防渗、防渗排(pai)水(shui)(shui)难(nan)题(ti),确保了(le)堤坝的(de)安全(quan)。
(2)施土程序大大简化。为了保证回滤层(ceng)的填筑宽度,传统使(shi)用(yong)山皮(pi)石时,要在(zai)石堤后面lm处加1根打桩扎围,这(zhei)需要花(hua)费大量的人力和物(wu)力。而且土工布料不需要这(zhei)道工序,使(shi)人力、物(wu)力大大节省,施土速度也大大加快。
(3)填(tian)(tian)筑材料的(de)选择受到限制(zhi)的(de)情况有所缓解。在土(tu)(tu)工(gong)布(bu)作(zuo)为反滤层之前,土(tu)(tu)工(gong)填(tian)(tian)筑堤(di)坝的(de)材料通常(chang)是堤(di)围区附近(jin)具有粘(zhan)性的(de)土(tu)(tu),当堤(di)围施土(tu)(tu)提速后,其粘(zhan)性土(tu)(tu)数量无法满足(zu)工(gong)程(cheng)要求(qiu)。但(dan)用(yong)(yong)土(tu)(tu)工(gong)布(bu)作(zuo)反滤层,填(tian)(tian)筑时可利用(yong)(yong)堤(di)围附近(jin)产生的(de)砂粉和中砂,使填(tian)(tian)筑材料具有更大的(de)选择性。
(4)降(jiang)低(di)工程(cheng)造(zao)价。①打桩扎围工序省(sheng)去了(le)50,000元/km,②2种(zhong)反滤层所用材(cai)料的差价节(jie)省(sheng)了(le)50%,达到60,000元/km,③更(geng)换填筑材(cai)料省(sheng)去了(le)350,000元/km,三种(zhong)材(cai)料共省(sheng)去了(le)460,000元/km。





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