取样方法对花岗岩残积土强度影响分析

Influence of Sampling Method on the Strength of Granite Residual Soil

花岗岩残积土具有很强的结构性,取样扰动会对其强度产生较大影响。使用3种不同的取样方法对花岗岩残积土进行取样,分析不同取样方法的取样效果,并对不同取样方法取得的试样进行了快剪试验和三轴不固结、不排水试验,基此,研究取样方法对花岗岩残积土强度的影响。结果表明:取样方法对花岗岩残积土强度影响很大,植物胶工艺钻孔取样比厚壁取土器取样效果好,对土体扰动较小;在直剪试验中,取样扰动对快剪强度影响主要体现在试样黏聚力大幅下降;在三轴试验中,取样扰动对土样不固结、不排水试验强度影响显著,扰动大的试样黏聚力和内摩擦角均大幅降低。

Granite residual soil has a sensitive structure,and sampling disturbance will have a greater impact on its strength.In order to study the effect of sampling method on the strength of Granite residual soil,in this paper,three different sampling methods are used to sample granite residual soil,and the sampling effects of different sampling methods are analyzed.Direct fast shear test and triaxial unconsolidated undrained test are carried out on the samples obtained by different sampling methods.The results show that the influence of different sampling methods on the strength of granite residual soil varies greatly,the effect of drill hole sampling with vegetable gum is better than that of thick-wall soil sampler,and the disturbance to soil is smaller.In direct shear test,the influence of sampling disturbance on the fast shear strength is mainly reflected in the significant decrease of cohesion of samples;in direct shear test,the influence of sampling disturbance on fast shear strength is mainly reflected in the sharp decrease of cohesion of samples;in triaxial test,sampling disturbance has a significant impact on the strength of unconsolidated undrained test of soil samples,and the cohesion and internal friction angle of samples with large disturbance are greatly reduced.