全回转钻机咬合桩施工技术应用

Application of 360 degree rotator drill in secant pile construction

全回转钻机适用于复杂地质情况钻孔施工,相对于传统旋挖钻及冲击钻,具有桩身垂直度控制较好、施工灵活等优点。通过在大连湾海底隧道沉管预制场咬合桩止水施工应用可知,全回转钻机可驱动套管做360°回转,压入套管和挖掘同时进行,无需依赖缓凝剂控制混凝土强度,并且不会出现由于单桩成桩时间过长,Ⅰ序桩混凝土强度过高导致无法进行Ⅱ序桩咬合施工的弊病,施工工效及质量均满足相关要求。

The 360 degree rotator drill is suitable for complex geological situations, which has the advantages of better verticality and convenient construction relative to traditional rotator drill and impact drill. Through the application of water stop secant pile construction in Dalian Bay subsea tunnel prefabricated yard, the 360 degree rotator drill can drive the sleeve to rotate 360 degree, and the pressing the casing and excavating can construct at the same time, without relying on the retarder to control the concrete strength, and it hasn’t happened that the Ⅱ-order secant pile construction couldn’t be carried out because the concrete strength of Ⅰ-order pile is too high due to the excessive pile time of single pile. The construction efficiency and quality of the secant pile are all met the relevant requirements.