沉(chen)井(jing)(jing)(jing)施(shi)(shi)工(gong)前，應(ying)詳細調查施(shi)(shi)工(gong)期間內的(de)(de)(de)洪汛、凌(ling)汛、河床沖涮、通航及漂流物等(deng)情(qing)(qing)況(kuang)，并根(gen)據調查情(qing)(qing)況(kuang)制(zhi)定具體措施(shi)(shi)，確保安全。沉(chen)井(jing)(jing)(jing)應(ying)用范(fan)圍：沉(chen)井(jing)(jing)(jing)可作為橋(qiao)梁墩臺的(de)(de)(de)深基礎，由(you)于(yu)平(ping)面尺寸小，而下(xia)沉(chen)深度比較大，因(yin)此(ci)，在橋(qiao)梁工(gong)程中廣泛采(cai)用。大型設(she)備基礎、地下(xia)倉庫、人(ren)防掩蔽所(suo)、盾構拼裝井(jing)(jing)(jing)、船塢塢首等(deng)均(jun)可采(cai)用沉(chen)井(jing)(jing)(jing)。正(zheng)常下(xia)沉(chen)時(shi)，沉(chen)井(jing)(jing)(jing)施(shi)(shi)工(gong)，應(ying)自中間向(xiang)刃腳處均(jun)勻對稱除(chu)(chu)土(tu)(tu)(tu)。排水除(chu)(chu)土(tu)(tu)(tu)下(xia)沉(chen)的(de)(de)(de)沉(chen)井(jing)(jing)(jing)底節，其設(she)計(ji)支承位置的(de)(de)(de)土(tu)(tu)(tu)，應(ying)在分層(ceng)除(chu)(chu)土(tu)(tu)(tu)中同時(shi)挖除(chu)(chu)。由(you)多個井(jing)(jing)(jing)室(shi)組成的(de)(de)(de)沉(chen)井(jing)(jing)(jing)，應(ying)控制(zhi)各井(jing)(jing)(jing)室(shi)之(zhi)間除(chu)(chu)土(tu)(tu)(tu)面的(de)(de)(de)高差，并避免(mian)內隔墻(qiang)底部(bu)下(xia)沉(chen)時(shi)受阻。

沉井(jing)(jing)預制完(wan)成并準(zhun)確就位后，開(kai)始抽(chou)(chou)除墊木。不(bu)論沉井(jing)(jing)大小(xiao)，此項工作(zuo)(zuo)均要求在(zai)2～4h內完(wan)成。抽(chou)(chou)除墊木前，頂管施(shi)工沉井(jing)(jing)，應對(dui)墊木分組編號，準(zhun)備回(hui)(hui)填(tian)用(yong)(yong)(yong)的(de)(de)(de)砂料(liao)，測(ce)量刃腳(jiao)標高和(he)沉井(jing)(jing)中線。沉井(jing)(jing)如發生偏(pian)斜可(ke)采用(yong)(yong)(yong)下列方法(fa)糾正(zheng)：在(zai)沉井(jing)(jing)高的(de)(de)(de)一(yi)(yi)(yi)側集中挖土。在(zai)低的(de)(de)(de)一(yi)(yi)(yi)側回(hui)(hui)填(tian)砂石。沉井(jing)(jing)高的(de)(de)(de)一(yi)(yi)(yi)側加重或者用(yong)(yong)(yong)高壓射水沖松(song)土層。沉井(jing)(jing)應用(yong)(yong)(yong)范圍：沉井(jing)(jing)可(ke)用(yong)(yong)(yong)作(zuo)(zuo)礦區的(de)(de)(de)豎(shu)井(jing)(jing)，面積比較小(xiao)，一(yi)(yi)(yi)般(ban)(ban)為圓形，施(shi)工沉井(jing)(jing)，直徑在(zai)15m以內。但下沉深(shen)度卻很深(shen)，一(yi)(yi)(yi)般(ban)(ban)要在(zai)100m以上(shang)，可(ke)用(yong)(yong)(yong)作(zuo)(zuo)上(shang)下人員(yuan)、材料(liao)、產(chan)品(煤和(he)礦石)的(de)(de)(de)豎(shu)向通道，同時還可(ke)作(zuo)(zuo)為豎(shu)向風道之用(yong)(yong)(yong)。

沉(chen)(chen)井(jing)(jing)應用(yong)范圍(wei)：埋置較深的(de)(de)構(gou)(gou)筑(zhu)物(wu)(wu)(wu)采用(yong)沉(chen)(chen)井(jing)(jing)法(fa)施(shi)(shi)(shi)工(gong)(gong)，從(cong)經(jing)濟(ji)和(he)技術角度來看，也比(bi)其他(ta)施(shi)(shi)(shi)工(gong)(gong)方法(fa)更為(wei)(wei)合理。給水(shui)(shui)排水(shui)(shui)工(gong)(gong)程的(de)(de)地(di)下(xia)(xia)(xia)構(gou)(gou)筑(zhu)物(wu)(wu)(wu)，多采用(yong)沉(chen)(chen)井(jing)(jing)。如江(jiang)心(xin)及(ji)(ji)岸邊的(de)(de)取(qu)水(shui)(shui)構(gou)(gou)筑(zhu)物(wu)(wu)(wu)、城市雨污(wu)水(shui)(shui)泵站下(xia)(xia)(xia)部結構(gou)(gou)等。沉(chen)(chen)井(jing)(jing)施(shi)(shi)(shi)工(gong)(gong)，沉(chen)(chen)井(jing)(jing)施(shi)(shi)(shi)工(gong)(gong)方法(fa)，實質(zhi)上(shang)就是將一(yi)個在地(di)面上(shang)事先(xian)澆(jiao)制(zhi)好(hao)的(de)(de)構(gou)(gou)筑(zhu)物(wu)(wu)(wu)通過挖土沉(chen)(chen)入到地(di)下(xia)(xia)(xia)一(yi)定深度后成為(wei)(wei)地(di)下(xia)(xia)(xia)構(gou)(gou)筑(zhu)物(wu)(wu)(wu)的(de)(de)施(shi)(shi)(shi)工(gong)(gong)過程。沉(chen)(chen)井(jing)(jing)基礎施(shi)(shi)(shi)工(gong)(gong)一(yi)般可分為(wei)(wei)早(zao)地(di)施(shi)(shi)(shi)工(gong)(gong)、水(shui)(shui)中筑(zhu)島(dao)及(ji)(ji)浮運沉(chen)(chen)井(jing)(jing)三(san)種。施(shi)(shi)(shi)工(gong)(gong)前應詳細了解(jie)場地(di)的(de)(de)地(di)質(zhi)和(he)水(shui)(shui)文條件。水(shui)(shui)中施(shi)(shi)(shi)工(gong)(gong)應做好(hao)河流汛期(qi)、河床沖刷、通航及(ji)(ji)漂(piao)流物(wu)(wu)(wu)等調查研究(jiu)，充分利用(yong)枯(ku)水(shui)(shui)季節，制(zhi)訂詳細的(de)(de)施(shi)(shi)(shi)工(gong)(gong)計劃及(ji)(ji)必要的(de)(de)措施(shi)(shi)(shi)，確保施(shi)(shi)(shi)工(gong)(gong)安全。