灌注桩孔壁粗糙度现场试验研究

结合常州高架桥一期工程现场成孔实测数据，探讨分层土灌注桩孔壁粗糙度的影响因素，结果表明:常规钻机采用单腰带钻头，有利于形成锯齿形的孔壁，从而获得较大孔壁粗糙度；旋挖机采用旋转挖掘，回转钻进成孔，形成孔壁较光滑，粗糙度较小；在成孔机具相同的情况下，孔壁粗糙度在砂土中相对较大，在粘性土中相对较小，并随钻孔深度增大，土层稳定性增加，粗糙度逐渐呈减小趋势，粗糙度随时间增长不明显。

Field Study of Wall Roughness of Bored Pile

Combined with the measured data of cast-in-place pile in the first-stage construction of Changzhou flyover crossing,the influencing factors of wall roughness of bored pile in layered soil are discussed in this paper.The results show that conventional drill machine with single-belt bit is favorable to form saw-shaped wall and thus get larger roughness;while rotary drilling machine adopts rotary boring to form smooth wall with smaller roughness.Under the same conditions of boring machine,wall roughness is relatively larger in sandy soil and smaller in clay soil,which will gradually decreased with drilling depth increased and soil stability improved.Roughness will not change significantly with time.