大埋深粗粒土勘察及物理力学特性试验研究

Geological exploration on properties of deep covered coarse grained soil and experimental research

随着我国大量的水利水电工程开工建设,良好的基岩坝基逐渐减少,不得不在深厚覆盖层地基上建设大坝,因此,深厚覆盖层地基的勘测是首先需要解决的问题。通过开挖后现场原位试验论证了大埋深下粗粒土物理力学特性。总结了大埋深下粗粒土勘察,统计分析了现场原位试验中干密度、平均粒径与土体承载力、变形模量、凝聚力之间的关系以及渗透系数与临界坡降之间的关系;通过对现场原位试验与室内试验结果进行对比研究,找出了室内试验凝聚力、内摩擦角、破坏及临界坡降值估算与原位试验对应值的统计规律。这些试验研究成果有助于提高深厚覆盖层的勘测工作效率,具有较大的工程应用价值。

With more and more construction of water conservancy and hydropower projects in China,good bedrock dam foundations are gradually decreased,and more deep overburden foundation remained. So the survey of deep overburden foundation is a primary problem to be solved in engineering. We study the law of the physical and mechanical properties of deep buried coarse grained soil after foundation pit excavation by in- situ test,summarize the survey methods,and analyze the relationship between dry density,average particle size and soil bearing capacity,deformation modulus,cohesion in the in- situ test by statistical analysis and analyze the statistical regularity between permeability coefficient and critical gradient in in- situ test. By comparative study between the in- situ tests and the laboratory tests,we have found the relationship between cohesion,internal friction angle,damage hydraulic gradient,critical hydraulic gradient in in- situ tests and the values in laboratory tests. The studies can help improve the efficiency of deep overburden survey work.