钻孔灌注桩在高压层位水地带的施工技术  

Research on Construction Technique of Perfusion into Boreholes at High Pressure Water Stratum

作　　者：边涛 张怀金 

机构地区：[1]中土尼日利亚有限公司,北京100038

出　　处：《铁道建筑技术》2013年第3期17-19,38,共4页Railway Construction Technology

摘　　要：在钻孔灌注桩的施工过程中,遇到高压层位水和流砂层是件处理起来比较困难的问题。当钻头钻进深度达到高压层位水时,地下水的压强值大于孔内标准泥浆在该截面处的压强值,高压层位水便会携带流砂涌入孔中,将孔内泥浆顶出孔外,层位水处孔壁固态物质的支撑随上升的水流逐渐减弱,致使该处出现无固态支撑的充水空洞,进而在该截面以上部位的孔壁发生连续坍塌。在阿夸依波州—阿比亚州50 km的AZUMINI中桥钻孔灌注桩施工中,就遇到了上述情况,采取了孔内增压、孔外减压和改良钻具的方法和工艺,有效地解决了高压层位水地带钻孔施工的技术难点。During perfusion into boreholes, high pressure water stratum and running sand always poses problems. When the drilling head reaches high pressure water stratum, the pressure of underground water is higher than the pressure of standard cement slurry at the contact surface, thus the high pressure water will gush out and push cement slurry out of the borehole. The holding power of solid substance around the wall of borehole at water stratum becomes weak gradually; subsequently there will be no solid substance to hold the hollow which is full of water, the walls of the borehole above the contact surface will collapse. The above situation occurred in the work of perfusion into boreholes for bridges at AZUMI- NI, the author then solved the technique bottle-neck of drilling method in high pressure water stratum effectively by increasing the pressure inside the boreholes and reducing the pressure outside of it, and improving the drilling gears.

关 键 词：钻孔灌注桩 高压层位水 孔内增压 孔外减压 

分 类 号：U443.154[建筑科学—桥梁与隧道工程]