基于Geddes解的取土器贯入引起的土体附加应力分析

Analysis of additional stress of soil induced by penetration of soil samplers based on Geddes solution

为了研究取土器贯入引起的土体扰动及附加应力分布特性,基于Geddes应力解,分别得到取土器管内任意一点处土样由于端阻力及侧壁摩阻力引起的竖向附加应力解,并通过数值方法对两者引起的管内土体附加竖向应力分布特性及取土器参数对其影响进行分析。计算结果表明:在取土器贯入过程中,端阻力的作用会引起土体产生一个由压应力转变为拉应力的过程,且其拉压应力不随取土器直径、贯入深度的变化而变化;增大取土器的直径能有效减少端阻力及侧壁摩阻力引起的轴线处土体的附加应力,考虑两者的共同作用,大直径取土器能较明显地提高取土样的质量。

In order to study the soil disturbance and distribution characteristics of the additional stress induced by the penetration of soil samplers,based on the Geddes solution,this study obtained the solution of the vertical additional stress of soil at any location in the soil sampler induced by the end resistance and side resistance,and analyzed the distribution characteristics of the vertical additional stress of soil in the soil sampler induced by the end resistance and side resistance and the influence of the sampler＇s parameters on the vertical additional stress of soil using a numerical method. The calculated results show that,during the penetration of soil samplers,the end resistance causes the compressive stress to change into the tensile stress in the soil,and the tensile stress does not vary with the soil sampler diameter and penetration depth. Increasing the diameter of the soil sampler can effectively reduce the additional stress of soil at the axis induced by the end resistance and side resistance,indicating that a larger-diameter soil sampler can significantly improve the quality of the soil sample in consideration of the effects of the end resistance and side resistance.