分類:技術(shu)知識發布時間:2015/10/30
在現(xian)場(chang)澆灌和鋼筋(jin)混凝土結(jie)構的(de)施(shi)工(gong)中,混凝土的(de)運(yun)輸和供應(ying)約(yue)占其總耗(hao)工(gong)時(shi)的(de)三分之一。在交通繁忙地(di)區和狹窄的(de)場(chang)地(di)進行高層或超(chao)高層建筑施(shi)工(gong)時(shi),需(xu)采用
混凝土拖泵
或(huo)泵車將混凝土輸送到施工(gong)(gong)現場。與傳統的輸送方式比較,拖泵或(huo)泵車既可(ke)減輕繁重(zhong)的體力勞動(dong),又(you)能進(jin)行連(lian)續(xu)作業(ye),從而縮短(duan)工(gong)(gong)期(qi),降低工(gong)(gong)程造價,提高(gao)工(gong)(gong)程質量。但采用
拖泵
或泵(beng)車泵(beng)送(song)時,除(chu)了要求設備本身(shen)性能良好外,對(dui)混凝土質量(liang)也有嚴(yan)格要求,否則也會造成堵管(guan),影響(xiang)施(shi)(shi)工進(jin)度。現將工程(cheng)施(shi)(shi)工中所遇到的堵管(guan)問(wen)題(ti)及解決(jue)辦法介紹如下。
1.原材料質量問題造成的堵管
在海南三亞一(yi)施(shi)工(gong)(gong)(gong)現(xian)場,施(shi)工(gong)(gong)(gong)方采(cai)用兩臺拖泵(beng)施(shi)工(gong)(gong)(gong),剛一(yi)開始泵(beng)送就(jiu)發(fa)生(sheng)堵管(guan)(guan)。當取出堵管(guan)(guan)處的(de)混(hun)凝(ning)土(tu)時,發(fa)現(xian)混(hun)凝(ning)土(tu)很干。經檢查(cha),配比正(zheng)常,但由于采(cai)用的(de)多孔骨料是一(yi)家工(gong)(gong)(gong)廠棄用的(de)廢渣,是一(yi)種不適合(he)拌(ban)制混(hun)凝(ning)土(tu)的(de)骨料。因其(qi)在高(gao)壓(ya)泵(beng)送過程中,水、漿(jiang)被(bei)壓(ya)入骨料孔隙,導致混(hun)凝(ning)土(tu)水分含(han)量偏低、流動(dong)性差,從(cong)而造成堵管(guan)(guan)。應急處理方法(fa)是,將這種有(you)孔骨料四周圍起來(lai),用自來(lai)水浸泡數天,使(shi)之(zhi)吸(xi)足水,并適當提高(gao)水泥的(de)比例,然后采(cai)用高(gao)壓(ya)小排量泵(beng)送,之(zhi)后就(jiu)不再發(fa)生(sheng)堵管(guan)(guan)了。
2.布(bu)管(guan)不當造成的堵管(guan)
在(zai)貴州六盤水一(yi)(yi)(yi)橋墩施工(gong)(gong)現(xian)場,采用同一(yi)(yi)(yi)公司生(sheng)產的(de)(de)(de)(de)兩臺(tai)拖(tuo)泵(beng)(beng)施工(gong)(gong),一(yi)(yi)(yi)臺(tai)放在(zai)山(shan)坡上向(xiang)(xiang)下泵(beng)(beng)送;另一(yi)(yi)(yi)臺(tai)放在(zai)山(shan)底(di)下水平泵(beng)(beng)送。結果,水平泵(beng)(beng)送的(de)(de)(de)(de)效果很好,而(er)(er)向(xiang)(xiang)下泵(beng)(beng)送的(de)(de)(de)(de)總是(shi)(shi)堵(du)管(guan)(guan)。檢查結果表明是(shi)(shi)布(bu)(bu)管(guan)(guan)不(bu)當造成的(de)(de)(de)(de)堵(du)管(guan)(guan)。因(yin)(yin)為向(xiang)(xiang)下泵(beng)(beng)送的(de)(de)(de)(de)混凝(ning)(ning)土(tu)會出現(xian)嚴(yan)重離析(xi),而(er)(er)用戶的(de)(de)(de)(de)布(bu)(bu)管(guan)(guan)方式是(shi)(shi)直線向(xiang)(xiang)下,未采取特殊(shu)措施。混凝(ning)(ning)土(tu)在(zai)向(xiang)(xiang)下泵(beng)(beng)送時,它的(de)(de)(de)(de)流動(dong)情況是(shi)(shi)輸送泵(beng)(beng)無(wu)法控制(zhi)的(de)(de)(de)(de),混凝(ning)(ning)土(tu)因(yin)(yin)自重而(er)(er)產生(sheng)向(xiang)(xiang)下自流的(de)(de)(de)(de)現(xian)象(xiang),從而(er)(er)產生(sheng)嚴(yan)重離析(xi),造成粗骨(gu)料(liao)(liao)(liao)流動(dong)快,在(zai)垂直管(guan)(guan)與水平管(guan)(guan)交接處(chu),粗骨(gu)料(liao)(liao)(liao)因(yin)(yin)積料(liao)(liao)(liao)而(er)(er)停(ting)止(zhi)前(qian)進(jin),而(er)(er)后面的(de)(de)(de)(de)細骨(gu)料(liao)(liao)(liao)、砂(sha)漿流動(dong)慢,使輸送管(guan)(guan)中(zhong)進(jin)入一(yi)(yi)(yi)些空(kong)氣(qi),這(zhe)些空(kong)氣(qi)會隨著混凝(ning)(ning)土(tu)的(de)(de)(de)(de)不(bu)斷(duan)泵(beng)(beng)送而(er)(er)逐步被壓縮回拖(tuo)泵(beng)(beng)出料(liao)(liao)(liao)口附近,形成空(kong)氣(qi)鎖,當其壓力(li)與泵(beng)(beng)送壓力(li)相近時,混凝(ning)(ning)土(tu)就無(wu)法泵(beng)(beng)送了,造成堵(du)管(guan)(guan)。按照技術要(yao)求重新布(bu)(bu)管(guan)(guan)后,堵(du)管(guan)(guan)現(xian)象(xiang)消(xiao)失。
3.混凝土配合比不當造成的(de)堵管
在福建龍(long)巖高速公路施工(gong)(gong)現(xian)場(chang),某施工(gong)(gong)單(dan)位采用同一(yi)廠家的(de)數十臺拖泵(beng)(beng)同時(shi)施工(gong)(gong),使用的(de)是商(shang)(shang)品混(hun)凝(ning)(ning)土(tu)。因工(gong)(gong)作線路長、混(hun)凝(ning)(ning)土(tu)需求量(liang)大,所以混(hun)凝(ning)(ning)土(tu)供(gong)應商(shang)(shang)就多,結果出現(xian)部分地(di)段(duan)的(de)拖泵(beng)(beng)泵(beng)(beng)送(song)(song)嚴重堵(du)管的(de)狀況。該公司的(de)工(gong)(gong)程師(shi)到(dao)現(xian)場(chang)了解情況后,斷定(ding)是混(hun)凝(ning)(ning)土(tu)質量(liang)有(you)問(wen)題。當檢查混(hun)凝(ning)(ning)土(tu)的(de)配合比時(shi)發現(xian),混(hun)凝(ning)(ning)土(tu)中(zhong)粗砂(sha)過多、中(zhong)砂(sha)很(hen)少。因粗砂(sha)的(de)吸(xi)水性、保(bao)水性和流動性都差,造成骨料在水泥漿中(zhong)分布不均勻而產(chan)生分層和離析,從而使泵(beng)(beng)送(song)(song)阻力增大。改(gai)用其他供(gong)應商(shang)(shang)的(de)混(hun)凝(ning)(ning)土(tu)后,泵(beng)(beng)送(song)(song)恢復正常。