不良地质条件下CFG桩充盈系数超常的影响因素分析及改进措施

Factors Affecting the Actual Filling Ratio of CFG Columns under Adverse Geological Conditions

长螺旋钻机钻孔、管内泵压CFG混合料成桩的施工工艺,具有施工噪音低,成桩速度快、工程造价低等特点,特别在一些复杂地层和不良地质条件下的安全施工更起到了重要的作用。结合西成铁路客运专线户县东站路基地基处理CFG桩施工,对液化不良地质条件下施工CFG桩充盈系数超常的影响因素进行分析及制定改进措施,并对改进效果进行了数据对比分析,将充盈系数控制在合理范围内,既保证了成桩质量,又起到了经济效益和社会效益,为以后类似液化不良地质地基CFG桩的施工起到了很好的借鉴作用。

The Cement-Fly Ash-Gravel （CFG） Column method is an effective soil improvement method and it has new develop- ments. The new procedures, such as, all-spiral-flight-auger drilling and pumping the filling material inside the borehole, have the characteristics of low construction noise, fast column installation, and cost effective. Under the adverse and complicated ge- ological conditions, these new techniques have made special contributions in a safe and successful CFG column installation. This paper presents a case history of the application of CFG columns in improving the liquefiable soils for Huxian East Station in the Xi＇an Chengdu passenger rail project. The excessive filling ratio of the CFG column under the adverse geological conditions is analyzed and factors affecting the filling ratio are presented. The mitigation measures that control the filling ratio are implemen- ted in the column installations. The results indicate that the project is a success.