反(fan)(fan)井(jing)鉆機(ji)廣泛用(yong)于(yu)市政建(jian)(jian)(jian)設、公路橋(qiao)梁(liang)、高層(ceng)建(jian)(jian)(jian)筑(zhu)等(deng)(deng)地基(ji)(ji)礎施(shi)工(gong)(gong)(gong)工(gong)(gong)(gong)程(cheng)，配合(he)不同鉆具(ju)，適應于(yu)干式(shi)（短螺旋(xuan)），或濕(shi)式(shi)（回轉斗）及巖層(ceng)（巖心鉆）的(de)成孔(kong)作業，反(fan)(fan)井(jing)鉆機(ji)具(ju)有裝機(ji)功(gong)率大(da)、輸出(chu)扭(niu)矩大(da)、軸向壓力大(da)、機(ji)動靈活，施(shi)工(gong)(gong)(gong)效(xiao)率高及多功(gong)能特點。反(fan)(fan)井(jing)鉆機(ji)施(shi)工(gong)(gong)(gong)適應我國大(da)部分地區的(de)土壤(rang)地質(zhi)條(tiao)件，使(shi)用(yong)范圍廣，基(ji)(ji)本可滿足橋(qiao)梁(liang)建(jian)(jian)(jian)設，高層(ceng)建(jian)(jian)(jian)筑(zhu)地基(ji)(ji)礎等(deng)(deng)工(gong)(gong)(gong)程(cheng)的(de)使(shi)用(yong)．目前，反(fan)(fan)井(jing)鉆機(ji)已被廣泛推廣于(yu)各種鉆孔(kong)灌注樁(zhuang)工(gong)(gong)(gong)程(cheng)。因(yin)此對反(fan)(fan)井(jing)鉆機(ji)的(de)施(shi)工(gong)(gong)(gong)工(gong)(gong)(gong)藝進行技術(shu)上探討有著(zhu)十分重要的(de)意(yi)義。

干成孔優缺點

?1、干成孔(kong)缺點：雖然無需擔心塌孔(kong)問題，但由于失去水和(he)泥漿的潤滑軟化、降溫及(ji)緩(huan)沖，某些地層鉆進阻力提升，特(te)別(bie)是密實的干土、粗砂層尤(you)為明顯，出現倒渣困難，加(jia)劇鉆齒(chi)損耗及(ji)鉆桿振動。

2、干(gan)成(cheng)孔(kong)優勢：除(chu)了工藝簡單、施工成(cheng)本(ben)低外，在特定地(di)質情況下，由于泥(ni)巖遇水軟化，泥(ni)漿(jiang)潤(run)滑，形(xing)成(cheng)打(da)滑、塞齒及湖底(di)現象。而干(gan)成(cheng)孔(kong)可消除(chu)上述(shu)現象，提(ti)升剪切破碎效率。

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