钻孔灌注桩旋挖工法几个关键问题的探讨
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摘要
旋挖工法是一种常见的钻孔灌注桩成孔方法。该工法在土层中成孔效率高,环保性好。当切削刃的齿尖压强不小于岩石单轴饱和抗压强度时,旋挖工法采取楔入、剪切破坏两种破岩方式钻进。破岩钻进时,因为旋挖工法的加压力由孔口产生,该加压力与孔底产生的阻碍钻头钻进的阻力共同作用下,在钻杆中产生弯矩,容易导致孔壁倾斜。性价比最好的旋挖工法是桩直径不大于2 m、桩长不大于60 m的钻孔灌注桩。
Rotary excavation method is a common method for drilling cast-in-place piles. This method has high efficiency and good environmental protection in soil layer. When the tip pressure of cutting edge is greater than the uniaxial saturated compressive strength of rock,rock-breaking ways are wedging and shear failure. Because the pressure of rotary excavation method is generated on the hole opening during rock-breaking drilling,bending moment in the drill pipe is produced by pressure and resistance which hinders drilling,easily leading to inclination of the hole wall.The best cost-effective rotary excavation method is used for bored cast-in-place pile with diameter less than 2 meters and length less than60 meters.
Rotary excavation method is a common method for drilling cast-in-place piles. This method has high efficiency and good environmental protection in soil layer. When the tip pressure of cutting edge is greater than the uniaxial saturated compressive strength of rock,rock-breaking ways are wedging and shear failure. Because the pressure of rotary excavation method is generated on the hole opening during rock-breaking drilling,bending moment in the drill pipe is produced by pressure and resistance which hinders drilling,easily leading to inclination of the hole wall.The best cost-effective rotary excavation method is used for bored cast-in-place pile with diameter less than 2 meters and length less than60 meters.
引文
[1]樊敬亮.机械回旋钻机穿越硬可塑黏性土层的关键施工工艺研究[J].河南科学,2017,35(9):1483-1486.
[2]许明,刘先珊,周泽宏,等.旋挖钻机钻进入岩判定与地层识别方法[J].中南大学学报(自然科学版),2017,48(12)3344-3349.
[3]高大钊.土力学与基础工程[M].北京:中国建筑工业出版社,2002:273-329.
[4]周云东,张书涵,王虎,等.倾斜地表下地下连续墙泥浆护壁稳定性分析研究[J].河南科学,2018,36(3):413-418.
[5]陈日胜,周翰斌.海上超长超深嵌岩钻孔灌注桩施工技术[J].施工技术,2012,41(5):52-56.
[6]赵伟,吴旭君,王召磊.旋挖灌注桩在沿海地区复杂地层中应用实例[J].岩土工程学报,2013,35(S2):1196-1199.
[7]王春.土钉墙-双排桩支护体系基坑变形特性分析[J].河南科学,2015,33(12):2160-2164.
[8]JGJ 106-2014,建筑基桩检测技术规范[S].
[9]JGJ 94-2008,建筑桩基技术规范[S].
[10]刘政治.嵌岩钻孔灌注桩入岩判定[J].施工技术,2009,38(S1):107-110.
[2]许明,刘先珊,周泽宏,等.旋挖钻机钻进入岩判定与地层识别方法[J].中南大学学报(自然科学版),2017,48(12)3344-3349.
[3]高大钊.土力学与基础工程[M].北京:中国建筑工业出版社,2002:273-329.
[4]周云东,张书涵,王虎,等.倾斜地表下地下连续墙泥浆护壁稳定性分析研究[J].河南科学,2018,36(3):413-418.
[5]陈日胜,周翰斌.海上超长超深嵌岩钻孔灌注桩施工技术[J].施工技术,2012,41(5):52-56.
[6]赵伟,吴旭君,王召磊.旋挖灌注桩在沿海地区复杂地层中应用实例[J].岩土工程学报,2013,35(S2):1196-1199.
[7]王春.土钉墙-双排桩支护体系基坑变形特性分析[J].河南科学,2015,33(12):2160-2164.
[8]JGJ 106-2014,建筑基桩检测技术规范[S].
[9]JGJ 94-2008,建筑桩基技术规范[S].
[10]刘政治.嵌岩钻孔灌注桩入岩判定[J].施工技术,2009,38(S1):107-110.