北京地区钻探工法对土工试验指标影响的研究

Research on Soil Testing Data Influence by Different Drilling Methods in Beijing Area

研究目的:确保高质量地搜集北京地区锤击取芯钻进和回转钻进工法土样的试验成果数据,分析不同工法试验指标的关系,针对北京段的地层条件,给选择可靠的备选钻探方法提供技术依据。研究方法:从定量的角度分析锤击取芯和回转钻进对土样试验指标的影响,在北京地区选择不同地质单元的工程进行试验指标对比分析。研究结果:根据北京地区的地质条件和沿线工程地质特征,在一般可塑地层采用孔内锤击取芯钻进方法钻进工法作为工程地质勘察的主要钻探方法,其它地层为辅助工法。研究结论:对2种工法的不同土样品进行对比,其空隙比、含水率、液性指数相差很小;用孔内锤击钻进压缩模量高15%左右。而软黏性土(IL≥0.75)、孔内锤击钻进对土工试验指标影响很大。

Research purposes： The aim of the research is to insure the collection of experimental data obtained with the methods of hammering core drilling and rotary drilling in Beijing area with high quality, to analyze the relation among different work methods and to provide reliable technical basis for the selection of substitute drilling method in allusion to the strata characteristics in Beijing area. Research methods： The analysis which influences soil sample test indices with methods hammering core drilling and rotary drilling is quantitatively. And some test indices obtained from different geological units in Beijing area are selected and studied contrastively. Research results： In accordance with the geological condition in Beijing area and geological properties along the purposed railway line, the hammering core drilling can be adopted as the primary work method in general geological layers. While in other strata, it can be one of the auxiliary methods. Research conclusions： After the contrastive study of different samples with the two work methods, there is little influence in void ration,water content, liquid index. The compressive modulus is higher 15 % in hammering core drilling. But, there is big influence index of soil testing in soft cohesive soil（IL ≥0.75）.