根據不同土(tu)質情(qing)(qing)況，沉(chen)井(jing)施(shi)工(gong)工(gong)藝，采(cai)用(yong)不同的(de)挖土(tu)順序(xu)，分層開挖，使挖土(tu)對稱均勻，刃腳均勻受(shou)力，沉(chen)井(jing)均勻、豎直(zhi)平(ping)穩下(xia)沉(chen)。采(cai)用(yong)剛性導(dao)(dao)管(guan)法進(jin)行水下(xia)混(hun)凝(ning)土(tu)封底(di)時，混(hun)凝(ning)土(tu)坍落度宜為150－200mm。封底(di)需用(yong)的(de)導(dao)(dao)管(guan)根數及間距應由導(dao)(dao)管(guan)作用(yong)半(ban)徑和(he)封底(di)面積確(que)定(ding)(ding)。沉(chen)井(jing)下(xia)沉(chen)前，合(he)肥沉(chen)井(jing)施(shi)工(gong)，應根據設(she)計單位提供(gong)的(de)地質資料決定(ding)(ding)是否需要增(zeng)補(bu)施(shi)工(gong)勘探，為編制施(shi)工(gong)技術方(fang)案提供(gong)準確(que)依據。施(shi)工(gong)前，應詳(xiang)細(xi)調查(cha)施(shi)工(gong)期間內的(de)洪(hong)汛(xun)、凌汛(xun)、河床沖涮、通航及漂流物等情(qing)(qing)況，并根據調查(cha)情(qing)(qing)況制定(ding)(ding)具體措施(shi)，確(que)保安全。

沉(chen)(chen)(chen)(chen)(chen)井下(xia)(xia)沉(chen)(chen)(chen)(chen)(chen)是(shi)沉(chen)(chen)(chen)(chen)(chen)井施工(gong)中(zhong)(zhong)一(yi)(yi)道(dao)非常重要的(de)工(gong)序(xu)，在(zai)(zai)(zai)挖土(tu)下(xia)(xia)沉(chen)(chen)(chen)(chen)(chen)過程(cheng)中(zhong)(zhong)若控制(zhi)(zhi)不好，就會出現(xian)質(zhi)量問題，所以在(zai)(zai)(zai)下(xia)(xia)沉(chen)(chen)(chen)(chen)(chen)過程(cheng)中(zhong)(zhong)必須采取(qu)嚴格(ge)的(de)質(zhi)量控制(zhi)(zhi)措施，并對常遇(yu)到的(de)問題進行原(yuan)因分析，總(zong)結出相應(ying)的(de)處理(li)方(fang)法(fa)。在(zai)(zai)(zai)井壁(bi)(bi)(bi)的(de)保護下(xia)(xia)，用機械和人工(gong)在(zai)(zai)(zai)井內挖土(tu)，使其(qi)在(zai)(zai)(zai)自重作用下(xia)(xia)沉(chen)(chen)(chen)(chen)(chen)入土(tu)中(zhong)(zhong)的(de)一(yi)(yi)種地(di)下(xia)(xia)構(gou)筑物，沉(chen)(chen)(chen)(chen)(chen)井施工(gong)公司，它具(ju)有結構(gou)剛性好、施工(gong)簡便(bian)、、節約(yue)投資以及加快施工(gong)進度等(deng)優點，在(zai)(zai)(zai)基礎工(gong)程(cheng)中(zhong)(zhong)得到了廣泛(fan)的(de)應(ying)用。在(zai)(zai)(zai)軟粘性土(tu)層中(zhong)(zhong)，對下(xia)(xia)沉(chen)(chen)(chen)(chen)(chen)系數不大的(de)沉(chen)(chen)(chen)(chen)(chen)井，采取(qu)連續挖土(tu)，連續下(xia)(xia)沉(chen)(chen)(chen)(chen)(chen)，中(zhong)(zhong)間(jian)停歇時間(jian)不要過長。采用射(she)水法(fa)即在(zai)(zai)(zai)井壁(bi)(bi)(bi)腔內的(de)不同高度處對稱(cheng)預埋射(she)水管，沉(chen)(chen)(chen)(chen)(chen)井快速施工(gong)，在(zai)(zai)(zai)井壁(bi)(bi)(bi)外側留有喇(la)叭口朝(chao)上(shang)方(fang)的(de)射(she)水嘴，遇(yu)下(xia)(xia)沉(chen)(chen)(chen)(chen)(chen)緩慢或停沉(chen)(chen)(chen)(chen)(chen)時，用高壓水射(she)水以減(jian)少井壁(bi)(bi)(bi)與土(tu)層之間(jian)的(de)摩阻力。

沉(chen)井(jing)(jing)下沉(chen)時(shi)，有時(shi)會產生偏斜、下沉(chen)速(su)渡過快或過慢等情(qing)形，此時(shi)應細心(xin)調(diao)(diao)查原(yuan)因，調(diao)(diao)劑挖土(tu)(tu)次序和(he)消除施工障礙，甚至借助卷揚機進(jin)行糾偏。沉(chen)井(jing)(jing)是靠自重下沉(chen)，要求(qiu)井(jing)(jing)壁盡可能(neng)(neng)增添重量，并減(jian)少井(jing)(jing)壁和(he)土(tu)(tu)層之間(jian)的摩擦力。磚(zhuan)、料(liao)石井(jing)(jing)壁的抗拉強(qiang)度小(xiao)，接縫多，整(zheng)體性差(cha)，透(tou)水(shui)(shui)才(cai)能(neng)(neng)強(qiang)；混(hun)凝土(tu)(tu)井(jing)(jing)壁整(zheng)體性好，防(fang)水(shui)(shui)才(cai)能(neng)(neng)強(qiang)，但(dan)抗拉強(qiang)度低，下沉(chen)過程中輕易(yi)(yi)開裂滲水(shui)(shui)。排水(shui)(shui)方式依(yi)據水(shui)(shui)量大小(xiao)，土(tu)(tu)質情(qing)形，裝備條件而(er)定。水(shui)(shui)量不大，土(tu)(tu)質較(jiao)好，一(yi)般采取簡易(yi)(yi)排水(shui)(shui)法或吊桶排水(shui)(shui)；水(shui)(shui)量較(jiao)大，土(tu)(tu)質較(jiao)差(cha)，應采用(yong)水(shui)(shui)泵抽水(shui)(shui)。