岩土工程勘察中冻土可钻性的影响因素分析

Analysis on the Influence Factors of Frozen Soil to Drillability in Geotechnical Engineering Investigation

摘要:

对含水率为13%~27%的粉质粘土，在0~-25 ℃之间进行冻结，测定冻土的单轴抗压强度、抗拉强度、抗剪强度、波速等。试验结果表明，当粉质粘土含水率在18%~25%，冻土温度为0~-18 ℃的条件下，温度一定时，随着含水率的增大，抗压、抗拉和抗剪强度总体呈降低趋势，可钻性级别呈降低趋势；含水率一定时，冻土的抗压、抗拉和抗剪强度随着温度的降低而增大，可钻性级别提高。冬季勘察时，受冻土影响，可通过在钻孔内加热水提高钻速的方法提高成孔效率。

关键词:冻土;温度;抗压强度;抗拉强度;可钻性;岩土工程勘察

Abstract:

The silty clay with water content of 13%~27% is frozen at 0 ~-25℃to measures the uniaxial compressive, tensile, shear strength and wave velocity of frozen soil. The test results show that when the silty clay water content is 18%~25% and the temperature of frozen soil is 0~-18℃, along with the increase of moisture content, the compressive, tensile and shear strength of frozen soil decrease under a certain temperature and drillability shows decreasing trend; at certain water content, along with the decrease of temperature, the compressive, tensile and shear strength of frozen soil increase and the drillability grade is improved. For the investigation in winter, the drilling speed can be improved by adding hot water in drilling hole to reduce the influence of frozen soil.

Key words:frozen soil; temperature; compressive strength; tensile strength; drillability; geotechnical engineering investigation