【摘要】 孔压静力触探（piezocone penetration test,CPTU）广泛应用于工程地质勘探中，但对浅层气地层的识别与探测精度方面还存在不足。基于CPTU贯入原理，分析了贯入过程中锥肩处土体的剪切变形特征，借助不同初始饱和度含气密砂的固结不排水三轴剪切试验，探讨了CPTU探头贯入饱和与含气砂层时锥肩处土体的超孔压响应规律及其差异性。结果表明：气体的存在显著影响砂土的剪切变形特性，且随着含气量增多，砂土剪切体变量增大，体变由剪胀过渡为剪缩；但土体孔压响应的敏感性却在降低，超孔压呈现出非负的典型特征，将其作为含气层识别的重要标志。针对分布于我国江浙沿海平原浅层气的储层物性特征，提出了基于原位多功能孔压静力触探触探的含浅层气地层精细识别方法。采用粉、细砂类土性辨识和超孔压非负特征构成“双控”指标进行初判，再结合多功能辅助参数做进一步检验校正。应用于工程实际，初步验证了该方法的有效性，提高了多层位含气层辨识的精度，可为浅层气地质区的岩土工程勘察与灾害防治提供借鉴。更多还原

【Abstract】 Although piezocone penetration test(CPTU) is widely used in engineering geological exploration, it has undeniable deficiencies in detection accuracy of shallow gas-bearing strata. Based on CPTU penetration principle, the shear deformation characteristics of soil at cone shoulder during penetration are analyzed. Furthermore, using the consolidated undrained triaxial shear test of dense gassy sand with different initial saturations, the response law and difference of excess pore pressure in soil at cone shoulder are discussed when CPTU probe penetrates into saturated and gas-bearing strata. The results show that, the presence of gas can significantly affect the shear deformation characteristics of sand, and with the increase of gas content, the shear volumetric strain increases, and transitions from shear dilatancy to shrinkage; however, the sensitivity of pore pressure response in soil decreases,leading to a non-negative characteristic phenomenon, which can be regarded as an important symbol of gas-bearing strata identification. According to the characteristics of shallow gas reservoir distributed in Jiangsu and Zhejiang coastal plain in China, a fine identification method of gas-bearing strata based on in situ multi-function piezocone penetration test is developed. In this method,the “dual control” index composed of silt or fine sand soil property identification and non-negative characteristics of excess pore pressure is used for preliminary judgment, and then combined with multi-functional auxiliary parameters for further inspection and correction. The validity of identification method is preliminarily verified in a practical engineering, and the identification accuracy of multi-layer gas-bearing strata is thereby improved.更多还原