含气细粒土孔压与应变关系的三轴试验研究

Triaxial Test Study on Relations Between Pore Pressure and Strain in Aerated Fine-Grained Soil

通过沸石的微孔吸附特性制作重塑细粒含气土,开展一系列不同有效围压的不排水剪切试验,研究含气量对重塑细粒土孔压变化规律和应变等值线的影响。在轴向应变达到5%之前,饱和土中孔压发展速度大于含气土的孔压;在轴向应变达到5%之后,含气土的孔压大于饱和土的孔压。在达到相同的应变下,含气土中产生的孔压更大,相应抗剪强度更小。在不同的含气量下,临界状态线的斜率M值是一个常数,M=1.25。不同含气量的土体在不同围压下有效应力路径上的应变等值线可视作直线,且其斜率随着应变的增加逐渐增大,最终与临界状态线重合。

A series of undrained shear tests with different effective confining pressures were conducted to study the effect of the gas content on pore pressure variation and strain isolines of remolded fine aerated soil based on the microporous adsorption properties of zeolite.Before the axial strain reached 5%,the pore pressure of saturated soil developed faster than that of aerated fine-grained soil,while the axial strain exceeded 5%,the pore pressure of aerated soil developed faster than that of saturated soil.In the same strain,the pore pressure in aerated soil was larger and the corresponding shear strength was smaller.In different contents of gas,the slope of the critical state line was a constant,it was 1.25.The strain isolines along the effective stress paths of soil with different contents of gas under different confining pressures could be regarded as straight lines,and their slopes increased gradually with the increase of strains and finally coincided with the critical state lines.